Claims
- 1. Seam forming apparatus for forming a seam near one lateral edge of each of one or more limp material segments, comprising:
- A. a fold assembly extending along a reference axis from an input end of said fold assembly to an output end of said fold assembly and including means establishing a first segment guide channel and a second segment guide channel, said first segment guide channel including means for receiving a first of said limp material segments, said first segment guide channel extending from said input end to said output end, and being open at said input end and at one lateral side thereof, and having a cross-section extending about an associated first channel axis extending substantially parallel to said reference axis near said output end and said second segment guide channel including means for receiving a second of said limp material segments, said second segment guide channel extending from said input end to said output end and having a cross-section extending about an associated second channel axis substantially parallel to said reference axis near said output end, said first and second channels being at least partially overlapped near said output end;
- B. positioning means for bidirectionally controlling the position of said lateral edges of said segments to be at associated predetermined positions with respect to said reference axis at a point along said reference axis between said input end and said output end of said fold assembly; wherein said positioning means comprises:
- first segment edge sensor near said input end of said fold assembly and including means for generating a first signal representative of the position of said lateral edge of said first segment within said first segment drive channel,
- first segment drive means responsive to said first signal for controlling said lateral edge of said first segment to be at it associated predetermined position,
- second segment edge sensor near said input end of said fold assembly and including means for generating a second signal representative of the position of said lateral edge of said second segment within said second segment drive channel, and
- second segment drive means responsive to said second signal for controlling said lateral edge to be at its associated predetermined position;
- said first and second segment drive means each including a rotatable drive wheel adapted for rotation about an axis substantially parallel to said reference axis, and having its lateral surface opposite to a platen substantially coincident with a surface of a respective one of said segment guide channels near said input end of said fold assembly;
- at least one of said platens and said drive wheel surface opposite thereto is positioned within the respective one of said segment guide channels; means for selectively biasing the lateral surfaces of said drive wheels and the respective ones of said platens toward each other and further including at least one selectively operable motor having an output shaft, and a means for coupling said output shaft to at least one of said drive wheels;
- wherein said coupling means includes a pair of rigid drive shafts coupling each of said drive wheels to a selectively operable motor and extending along a drive shaft axis substantially parallel to said reference axis, said drive shafts pivotal about an axis substantially perpendicular to said drive shaft axis at a point distal from said drive wheels, and actuator means for selectively moving said drive shafts between two positions whereby at one of said positions said drive wheels are biased towards and adjacent to respective ones of said platens, and at the other of said positions said drive wheels are biased away from the respective ones of said platens.
- 2. Apparatus according to claim 1 wherein a cross-section of said first segment guide channel and said second segment guide channels are substantially V-shaped and oppositely directed and interleaved near said output end.
- 3. Seam forming apparatus for forming a seam near one lateral edge of each of one or more limp material segments, comprising:
- A. a fold assembly extending along a reference axis from an input end of said fold assembly to an output end of said fold assembly and including means establishing a first segment guide channel and a second segment guide channel, said first segment guide channel including means for receiving a first of said limp material segments, said first segment guide channel extending from said input end to said output end, and being open at said input end and at one lateral side thereof, and having a cross-section extending about an associated first channel axis extending substantially parallel to said reference axis near said output end and said second segment guide channel including means for receiving a second of said limp material segments, said second segment guide channel extending from said input end to said output end and having a cross-section extending about an associated second channel axis substantially parallel to said reference axis near said output end, said first and second channels being at least partially overlapped near said output end;
- B. positioning means for bidirectionally controlling the position of said lateral edges of said segments to be at associated predetermined positions with respect to said reference axis at a point along said reference axis between said input end and said output end of said fold assembly; wherein said positioning means comprises:
- first segment edge sensor near said input end of said fold assembly and including means for generating a first signal representative of the position of said lateral edge of said first segment within said first segment drive channel,
- first segment drive means responsive to said first signal for controlling said lateral edge of said first segment to be at its associated predetermined position,
- second segment edge sensor near said input end of said fold assembly and including means for generating a second signal representative of the position of said lateral edge of said second segment within said second segment drive channel, and
- second segment drive means responsive to said second signal for controlling said lateral edge to be at its associated predetermined position;
- said first and second segment drive means each including a rotatable drive wheel adapted for rotation about an axis substantially parallel to said reference axis, and having its lateral surface opposite to a platen substantially coincident with a surface of a respective one of said segment guide channels near said input end of said fold assembly;
- at least one of said platens and said drive wheel surface opposite thereto is positioned within the respective one of said segment guide channels;
- means for selectively biasing the outer surfaces of said drive wheels and the respective ones of said platens toward each other and further including at least one selectively operable motor having an output shaft, and slide assembly means for coupling said output shaft to at least one of said drive wheels; wherein said slide assembly means includes a pair of rigid drive shafts coupling each of said drive wheels to a pair of drive shaft arms coupling each of said drive shafts to a selectively operable motor and extending along a second axis substantially perpendicular to said reference axis, said drive shafts moveable along an axis substantially parallel to said second axis, and actuator means for selectively moving said drive shafts between two positions whereby at one of said positions said drive wheels are biased towards and adjacent to respective ones of said platens, and at the other of said positions said drive wheels are biased away from the respective ones of said platens.
- 4. Apparatus according to claim 3 wherein said slide assembly further comprises a second drive arm substantially perpendicular to said reference axis for slidably engaging said actuator to enable said drive shafts to slidably move between said two positions.
- 5. Apparatus according to claim 4 wherein said second drive arm further comprises at least one pressure platform, said pressure platform selectively biased against a spring means for moderating said drive shaft movement.
- 6. Apparatus according to claim 3 wherein a cross-section of said first segment guide channel and said second segment guide channels are substantially V-shaped and oppositely directed and interleaved near said output end.
CROSS REFERENCE TO RELATED PATENT APPLICATIONS
This application is a continuation-in-part of our co-pending U.S. Pat. Application Ser. No. 318,656 filed Mar. 3, 1989. The disclosure of U.S. Pat. Application Ser. No. 318,656 is hereby incorporated by reference.
This invention relates to drive assemblies for seam-forming apparatus of systems for automatic or computer-controlled manipulation of sheet material during processing, e.g., fabric or other limp material to be assembled at a sewing station.
During the construction of a useful item from raw stock of flat goods (e.g., cloth, paper, plastic, and film), it is often necessary to precisely position and guide the flat goods through a work station. Typical work stations perform assembly operations such as joining, cutting or folding. For example, such work stations can be equipped with sewing machines for joining multiple layers of limp fabric, such as may be from separate limp material segments, or from several regions of the same (folded) limp material segment.
Conventionally, the positioning and guiding of the fabric-to-be-joined is accomplished by skilled human operators. The operators manually feed or advance the fabric-to-be-joined through the stitch forming mechanism of the sewing machine along predetermined seam trajectories on the fabric. The resultant seams can be straight or curved, or a combination of both as is often required in the assembly of fabric panels to form articles of clothing, for example. Typically, the fabric-to-be-joined must be precisely positioned and accurately directed to the sewing head to achieve the desired seam. The human operator must therefore function not only as a "manipulator" of the fabric but also as a real-time "sensing and feedback medium", making small adjustments, e.g., in orientation, fit-up and seam trajectory, to obtain quality finished goods. The adjustments are required, for example, due to variations in seam type, geometry, location and fit-up.
In the prior art, to assist in the formation of such a seam, an operator manually presents and feeds two limp material segments to be joined to a fold assembly coupled to a sewing machine. The fold assembly, for example, a Simanco USA model 230056, is adapted to receive the presented segments and to guide the edges so that at the output end of the fold assembly, the two segments emerge with their lateral edges interlocked and ready for joining. The fold assembly is positioned so that the emerging segments are driven by the feed dogs of the sewing machine to the needle and bobbin assembly of the sewing head of the machine.
One drawback of this technique is that it is labor intensive; that is, a large portion of the cost for manufacture is attributable to manual labor. An additional drawback is introduced when the material is being fed on off-the-arm sewing machines, such as those used for sewing seams in pant legs or sleaves. The fold assemblies in the prior art do not accommodate the special situation of feeding material to be sewn into a tube shape. In that situation, the material and construction of the sewing machine often makes it difficult and awkward for the human operator to maintain an even feed of fabric.
To reduce labor cost in the clothing assembly industry, automated or computer-controlled manufacturing techniques have been developed for many of the desired assembly operations. However, even the manual assisted techniques have limited effectiveness due to the required degree of human intervention and are limited in their ability to accommodate curved seams and seams forming a tube, such as pant legs or sleaves.
Accordingly, it is an object of the invention to provide an improved drive assembly for positioning and guiding sheet material, e.g., fabric or other limp material to be processed, in the formation of seams with off-the-arm machines.
It is another object of the present invention to provide an improved drive assembly suitable for automatic or computer-controlled seam forming operations on an off-the-arm sewing machine, which is of simple, rugged, versatile, and economical design.
These and other objects of the invention are accomplished by an improved drive assembly for controlling the position of sheet material, e.g., fabric or other flat goods, slidingly supported on a work surface with a relatively low coefficient of friction, with an off-the-arm sewing machine.
The present invention is a seam forming apparatus for forming a seam at one lateral edge of one limp material segment (e.g., an edge finishing seam, such as a hem), or at one lateral edge of each of two limp material segments.
The apparatus includes a fold assembly extending along a reference axis from an input end to an output end. The fold assembly establishes a first segment guide channel adapted to receive a first of the limp material segments. That first segment guide channel extends from the input end to the output end, and is open at the input end and at one lateral side.
In some forms of the invention adapted for joining two limp material segments, the fold assembly also establishes a second segment guide channel adapted to receive the second of the limp material segments. That second segment guide channel also extends from the input end to the output end, and is open at the input end and at one lateral side.
The first and second segment guide channels each extend about an associated channel axis extending substantially parallel to the reference axis near the output end of the fold assembly.
For a full felled seam, the two segment guide channels of the fold assembly have substantially V- (or C--) shaped cross sections, and the first and second channels are oppositely directed and interleaved near the output end. As used herein, the terms "V-" and "C-" ar used interchangeably to define a shape which curves about a central point, either in a continuous or piecewise continuous manner.
In one form, the invention further includes two feed plane support members. That first feed plane support member has a segment support surface extending substantially to the lower surface of the portion of the first segment guide channel above its associated channel axis at the input end of the fold assembly. The second feed plane support member has a material support surface extending substantially to the lower surface of the portion of the second segment guide channel at the input end of the fold assembly.
A position controller controls the position of the lateral edges of the segments in the channels to be at associated predetermined positions measured with respect to the reference axis at a point along that axis between the input and output ends of the fold assembly. Generally, the controlled edges are laterally spaced apart from the reference axis by an associated predetermined distance near the input end of the fold assembly. The segment edge positions are controlled bidirectionally, and pursuant to a closed loop control system.
In various forms of the invention, the position controller includes segment edge sensors between the input end and output end of the fold assembly. Those edge sensors are adapted to generate position signals representative of the positions with respect to the reference axis of the lateral edges of the limp material segments in their respective channels. Segment drivers are responsive to the position signals for controlling the lateral edges of the segments to be at their associated predetermined positions.
Preferably, the edge sensors are positioned between the segment drivers and the output end of the fold assembly, although in some forms, this configuration may be reversed.
The segment drivers each include a rotatable drive wheel adapted for rotation about an axis substantially parallel to the reference axis. The wheels have their respective lateral surfaces opposite to a platen substantially coincident with a surface of a respective one of the segment guide channels near the input end of the fold assembly.
Preferably, at least one of the platens and the drive wheel surface opposite thereto is positioned within the respective one of the segment guide channels.
The preferred form of the invention is further adapted to selectively bias the outer surfaces of the drive wheels toward their respective platens. By differentially biasing the drive wheels toward their respective platens, differing drags may be established in the two segments, so that a desired relative stretching may be achieved. The lateral surfaces of the drive wheels may selectively be positioned away from their respective platens to permit easy loading of segments to the fold assembly. With the wheels biased toward their respective platens, drive motors coupled to the wheels control the rotational motion of the wheels, together or independently, to establish control of the limp material segment positions within the fold assembly.
In forms of the present invention adapted for off-the-arm sewing machines, the segment drivers are an integral part of a drive assembly. The drive assembly may include drive shafts which couple each of the drive wheels to an associated, selectively operable motor. In one form, the drive shafts are coupled to an actuator for selective pivotal movement between two positions, whereby at one position the drive wheels are biased towards and adjacent each respective platen, and at another position the drive wheels are biased away from each respective platen. In an alternate form, the drive shafts are each coupled to a drive arm assembly, each of which is slidable along a second axis, substantially perpendicular to the reference axis, for moving the drive shafts between the two positions. In a first position for each arm, its drive wheel is biased toward its platen, and in a second position its drive wheel is biased away from that platen.
The above-described seam forming apparatus may be integrated with the sewing head and feed dog assembly of a sewing machine to form an automated full felled seam forming system. With this configuration, two segments-to-be-joined may be readily loaded in separate (and overlapping) feed planes to the fold assembly. Then, the sewing head may be actuated so that the feed dog assembly draws the two segments through the fold assembly to the needles of the sewing head. As the segments are drawn through the fold assembly, the position of the lateral edges are dynamically controlled to establish a high quality seam.
While particularly adapted for use with an off-the-arm sewing machine, these forms may also be used with other machine configurations.
US Referenced Citations (20)
Foreign Referenced Citations (2)
| Number |
Date |
Country |
| DL132508 |
Oct 1978 |
DEX |
| 2090298A |
Dec 1981 |
GBX |
Patent Grant
5031552
