Embodiments relate generally to sewing machines, and more particularly to industrial sewing machines having the capability of sewing relatively thinner materials and relatively thicker materials, and related methods.
Industrial sewing machines are often used for sewing together materials of different combined thicknesses. When material is being sewn on a sewing machine, the material rests on a throat plate or needle plate. A presser foot presses on the top of the material and an upper walking foot or top feed dog helps to feed the material as the material is sewn by a needle or needles. The thickness of the material which can be sewn by the machine is dictated by the clearance between the throat plate below the material and the needle, presser foot, and upper walking foot above the material. The throat of the machine is the space between the throat plate and the needle, presser foot, and upper walking foot. Sewing machines used for sewing both thinner and thicker materials will generally have the ability to adjust the throat or vertical clearance of the presser foot and upper walking foot for the material to fit through the throat of the machine.
Some industrial sewing machines capable of sewing thinner and thicker materials utilize an upper walking foot and a lower feed dog (sometimes referred to as “top and bottom feed”) and are configured to impart out-of-phase reciprocatory movement of the presser foot and upper walking foot. In these types of sewing machines, the upper walking foot travels in a more or less elliptical motion during sewing, and thus has a horizontal motion component (stepping length or feed length) and a vertical motion component (stepping height). Some industrial sewing machines capable of sewing thinner and thicker materials include adjustment mechanisms, multiple drive shafts, and linkage assemblies that add to the complexity of the sewing machine. Proper adjustment of the stepping height of the upper walking foot is typically a manual and/or time-consuming process.
Accordingly, and despite the various advances already made in this field, there is a need for further improvements related to providing sewing machines with an ability to readily adjust the stepping height to more quickly and easily configure the machine for sewing thicker and thinner materials on demand.
Generally, a kit for adding or replacing an automated upper walking foot stepping height adjustment to a sewing machine is described and comprises a mounting assembly including an actuator bracket, an actuator coupled to the actuator bracket, a drive assembly, and a needle drive assembly. The actuator includes an actuator shaft that extends and retracts. The drive assembly includes a drive shaft, a drive arm coupled to the drive shaft and the actuator shaft, and a guide coupled to the drive shaft. The needle drive assembly includes a variable drive crank coupled to the guide and configured to couple to a needle drive shaft of a sewing machine. Selectively extending and retracting the actuator shaft selectively adjusts a stepping height of an upper walking foot.
In some embodiments, selectively extending and retracting the actuator shaft sets an uppermost travel limit of a presser foot. The needle drive assembly may include a needle drive shaft coupled to the variable drive crank. The needle drive assembly may include a needle drive lever coupled to the needle drive shaft and configured to drive a needle assembly of a sewing machine. The needle drive assembly may include a needle drive crank coupled to the needle drive shaft and configured to couple to a crank arm of a sewing machine, and the crank arm drives the needle drive assembly. The kit may include a pin, and the variable drive crank may include an elongated slot and the pin moves within the slot, and selectively extending and retracting the actuator shaft adjusts a position of the pin along a length of the slot. The kit may include a cover configured to replace an existing cover of the sewing machine and the actuator bracket is coupled to the cover. The kit may include a control coupled to the actuator, and a user selectively extends and retracts the actuator shaft using the control.
Generally, a sewing machine with an automated upper walking foot stepping height adjustment is described and comprises a mounting assembly including an actuator bracket, an actuator coupled to the actuator bracket, a drive assembly, a needle drive assembly, an upper walking foot, and a needle assembly. The actuator includes an actuator shaft that extends and retracts. The drive assembly includes a drive shaft, a drive arm coupled to the drive shaft and coupled to the actuator shaft, and a guide coupled to the drive shaft. The needle drive assembly includes a needle drive shaft, a needle drive lever coupled to the needle drive shaft, a variable drive crank coupled to the needle drive shaft and the guide, and a needle drive crank coupled to the needle drive shaft. The upper walking foot is coupled to the variable drive crank. The needle assembly is coupled to the needle drive crank. Selectively extending and retracting the actuator shaft adjusts a stepping height of the upper walking foot.
In some embodiments, the sewing machine may include a presser foot coupled to the variable drive crank, and selectively extending and retracting the actuator shaft sets an uppermost travel limit of the presser foot. The sewing machine may include a control coupled to the actuator, and a user selectively extends and retracts the actuator shaft using the control. The sewing machine may include a pin, and the variable drive crank may include an elongated slot and the pin moves within the slot, and selectively extending and retracting the actuator shaft adjusts a position of the pin along a length of the slot.
A method of adjusting a stepping height of an upper walking foot of a sewing machine is described and includes selectively extending and retracting an actuator shaft, and actuating a guide and variable drive crank to adjust the stepping height of the upper walking foot. The method may include actuating the guide and variable drive crank to adjust the stepping height of a presser foot.
A method of adding or replacing an automated upper walking foot stepping height adjustment to a sewing machine is described and includes installing a mounting assembly including an actuator bracket to a sewing machine, coupling an actuator with an actuator shaft that extends and retracts to the actuator bracket, coupling a drive arm to the actuator shaft, coupling the drive arm to a drive shaft, coupling a guide to the drive shaft, and coupling a variable drive crank to the guide and a needle drive shaft of the sewing machine.
In some embodiments, the method of adding or replacing an automated upper walking foot stepping height adjustment to a sewing machine may include providing a needle drive shaft and coupling the variable drive crank to the needle drive shaft. The variable drive crank may include an elongated slot, and the method may include coupling a pin to the guide and the pin moves within the slot of the variable drive crank. The method may include coupling a presser foot to the variable drive crank. The method may include coupling a stepping height control to the actuator.
A method of manufacturing a sewing machine with an automated upper walking foot stepping height adjustment is described and includes installing a mounting assembly including an actuator bracket to a sewing machine, coupling an actuator with an actuator shaft that extends and retracts to the actuator bracket, coupling a drive arm to the actuator shaft, coupling the drive arm to a drive shaft, coupling a guide to the drive shaft, coupling a variable drive crank to the guide and a needle drive shaft, coupling a needle drive lever to the needle drive shaft, coupling a needle assembly to the needle drive lever, and coupling an upper walking foot to the variable drive crank.
In some embodiments, the method of manufacturing a sewing machine with an automated upper walking foot stepping height adjustment the variable drive crank includes an elongated slot and the method includes coupling a pin to the guide, and the pin moves within the slot of the variable drive crank. The method may include coupling a presser foot to the variable drive crank. The method may include coupling a stepping height control to the actuator.
Additional aspects and advantages of the invention will become more apparent upon further review of the detailed description of the illustrative embodiments taken in conjunction with the accompanying drawings.
Referring to
Generally, a variable drive assembly 100 is described herein and includes the components needed to add an automated upper walking foot stepping height adjustment to a sewing machine 10. In some embodiments, the variable drive assembly 100 may include the components needed to replace an upper walking foot stepping height adjustment of a sewing machine 10. The variable drive assembly 100 may also allow for automated adjustment of the uppermost travel limit of the presser foot 18. Allowing for adjustment of the uppermost travel limit of the presser foot 18 may minimize presser foot spring deflection thereby minimizing the likelihood of the presser foot floating on the material and thereby improve the performance of the sewing machine 10, for example.
In some embodiments, the variable drive assembly 100 can be installed without additional modifications to the sewing machine 10. The variable drive assembly 100 may be configured such that the modifications to the sewing machine can be completed with hand tools. The variable drive assembly 100 may be configured such that installation can be completed by someone of ordinary technical skill instead of requiring precision machine shop modifications and factory trained technicians to complete the installation, for example. The variable drive assembly 100 may be part of a kit to convert a sewing machine 10 from a manual upper walking foot stepping height adjustment to an automated upper walking foot stepping height adjustment. In some embodiments, the variable drive assembly 100 described herein may be part of a complete sewing machine.
In this illustrative embodiment, the variable drive assembly 100 simplifies the design of the sewing machine 10 by reducing the number of shafts and/or linkages of the sewing machine 10. The variable drive assembly 100 allows for a single common drive shaft for driving the needle assembly 16, the presser foot 18, and the upper walking foot 20. By reducing the number of shafts and/or linkages of the sewing machine 10, the variable drive assembly 100 may improve the reliability and/or serviceability of the sewing machine 10.
Referring to
In this illustrative embodiment, the outer block 140 is mounted to the bracket 122, the bracket 122 is mounted to the outside 114 of the cover 112, and the inner block 142 is mounted to the inside 116 of the cover 112. The cover 112 is mounted to a needle housing 24. The cover 112, as part of the variable drive assembly 100 describe herein, replaces a needle housing cover on an existing sewing machine. The outer block 140 and inner block 142 each include a drive shaft bearing 144. The inner block 142 also includes a needle drive shaft bearing 146. In this illustrative embodiment, the bearings 144, 146 are needle bearings. In some embodiments, the bearings 144, 146 may be ball bearings and/or sleeve bearings, for example.
The drive assembly 160 includes a pivot 162, a drive arm 164, a drive shaft 166, and a guide 168. The actuator shaft 134 is coupled to the pivot 162, the pivot 162 is pivotally connected to a first end 170 of the drive arm 164, and a second end 172 of the drive arm 164 is coupled to a first end 174 of the drive shaft 166. The drive shaft 166 passes through the outer block 140, bracket 112, cover 112, and inner block 142 and is rotatably supported by the bearings 144. The guide 168 is coupled to a second end 176 of the drive shaft 166. The guide 168 includes a recessed groove 178.
The needle drive assembly 180 includes a needle drive shaft 182, a needle drive lever 184, a variable drive crank 186, and a needle drive crank 188. The variable drive crank 186 includes a hole 190 for mounting the variable drive crank 186 onto the needle drive shaft 182 and a longitudinal slot 192 for a pin 194. The pin 194 includes a wear disc 196. As illustrated in
Referring to
When the actuator shaft 134 is in the retracted position, as shown in
Referring to
In this illustrative embodiment, the upper walking foot 20 has two stepping height positions, i.e. the low stepping height and the high stepping height, due to the two position operation of the actuator 130. A user selectively adjusts the stepping height. In some embodiments, the variable drive assembly 100 includes a stepping height control 136 allowing a user to selectively adjust the stepping height. In this illustrative embodiment, the stepping height control 136 is a toggle switch. In some embodiments, the stepping height control 136 is a selector switch, for example. In some embodiments, the variable drive assembly 100 includes a stepping height control mounting bracket 137. In some embodiments, alternate actuators allow for the stepping height of the upper walking foot 20 to be continuously or infinitely variable between the high stepping height (
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While the present invention has been illustrated by the description of specific embodiments thereof, and while the embodiments have been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such detail. The various features discussed herein may be used alone or in any combination within and between the various embodiments. Additional advantages and modifications will be readily apparent to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope or spirit of the general inventive concept.
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Entry |
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Pegasus Sewing Machine Mfg. Co., Ltd, EXT Series Technical Manual, Cat. No. 9725, Oct. 1996, 35 pgs. |
Number | Date | Country | |
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20230250569 A1 | Aug 2023 | US |