Patent Application
20100282149
1. Field of Invention
The present invention relates to a manually operated sewing machine system. More particularly, the present invention relates to a custom machine having a square needle feed and jump foot system capable of using thread sizes from 69 through 346, inclusive, and standard 328 System needles.
2. Description of Prior Art
While there are other sewing machines available on the market for applications in and other residential, commercial, and industrial applications, the machines historically consist of lighter and weaker frames and components and are not capable of extension to heavy-duty applications and use as a permanent application in most instances. In the industry, in which the inventor has been engaged for 26 years, there is a need for an improved system for reliably, rapidly, and economically sewing heavy materials, with relatively easy replacement of integral parts of the machine(s) and system(s).
The present invention provides an improved, effective and efficient manually operated sewing machine system for sewing up to ¾″ thickness of heavy materials such as leather, canvas, and nylon webbing, without loss of function in sewing light to medium weights and thicknesses of fabrics and materials. A hand crank or hand wheel operated sewing machine, capable of being connected to a motor, featuring a square or “box” needle feed system with a jump foot. The synchronized motion of the needle, jump foot, and shuttle hook is accomplished using three (3) fixed cams and a rack and pinion drive for the shuttle hook. The primary hook cam drive is located anterior to the top cam shaft. The precise design of the primary hook drive cam governs the motion of the rack and pinion spring loaded shuttle hook system. The hook collects thread on a return spring action. The cam pushes down against a nylon roller located at the top of the rack, pushing against the spring-loaded rack and pinion. The shuttle hook backs up as the hook shaft drive gear turns, driven down by the gear rack against the pressure of a return spring. The shape of the cam allows the rack to spring up rapidly during forward turning motion, allowing the shuttle hook to move forward rapidly, catching the thread off the needle at a point when the needle has risen 3/16 inch from the lowest point of its travel. The shuttle hook continues its rapid movement, carrying the thread around the shuttle and bobbin thread to a point beyond 180 degrees to allow the needle thread to easily clear the entire shuttle assembly. The shuttle hook cam then allows the gear rack to push down slightly, positioning the finger of the hook driver back to the 180 degree position, setting the hook driver finger and the heel of the shuttle hook in the vertical (“twelve O′Clock”) position and allowing the easy escape of the needle thread through the gap between the hook driver finger and the heel of the shuttle hook. The return spring mechanism cam allows the assembly to pause in this position until the needle bar can travel to its highest point, with the needle bar serving as the thread takeup and pulling the bobbin thread with the needle thread into the material being sewn. An alternative cam can be used which does not kick the shuttle hook back to the 180 degree position and the thread release point remains beyond the 180 degree point. The needle feed cam is located on the cam shaft at the front of the machine. The needle bar is driven down by the action of a link driver and the pin, which is positioned on the needle feed cam and timed to coincide with the movement of the needle feed action.
Sequential movement is as follows:
The needle bar is driven downward by the motion of the pin on the cam, which drives the link connected to the needle bar. Thus, the needle inserted in the base of the needle bar is driven through the material being sewn, of up to ¾ inch thickness, to the bottom of the stroke of its movement.
The cam's outer circumferential surface, which rides on a lip of the needle bar frame and also is used to hold the needle bar frame against resting pads, rotates to produce the preferred motion of the needle. The cam is shaped precisely to cause the needle bar frame to snap forward, creating the proper length and space of stitch. Setting the stitch length from 0 to ¼ inch is accomplished with a simple thumb screw protruding through the front of the machine and contacting the needle bar frame, stopping its spring-loaded return at the desired point to produce the correct stitch length.
The snap motion helps to ensure the shape of the square feed motion on the lower end of the needle bar action. The top of the needle feed motion is an arc movement, which is not critical to the square feed of the needle through the material. This movement can best be described as a Ninety Degree Arc Snap Movement or Traverse.
The jump foot cam is located on the camshaft directly below a cam follower pin extending through the frame. Timed to the movement of the needle bar, the jump foot controlling cam rotates to its high point, pushing against the cam follower pin. Thus, the adjustable screw protruding through the lift lock lever above it. A compensating pressure foot bar slides easily through the opposite end of the lift lock lever when in its neutral position, thus adjusting to the thickness of the materials held by the presser foot at the bottom of the bar.
As the action of the jump foot cam pushes the end of the lift lock lever up, the lever tilts so that the pressure foot bar is pinched and lifted as well. The pressure foot bar extends through a spring, which spring is spring-loaded to apply constant downward pressure. Therefore, as the cam pushes against the lever and pinches the bar, the spring is compressed as the bar is lifted, raising the jump foot off the material. As the cam rotates to its low point, the lift lock lever is released returning to its neutral position and releasing the presser foot bar so that the foot rests once again on the material and holds it in position for the next stitch.
The present invention involves a sewing machine device with a square feed, needle feed with jump foot system capable of using thread sizes 69 through 346, inclusive, and standard 328 system needles ranging in size from 140 (#22) to 230 (#26). The machine will be able to sew from light material up to and including approximately ¾ inch of leather, when manually operated. It features a hand crank or hand wheel, capable of being connected to a motor, and utilizes a square or “box” needle feed system with a jump foot. The synchronized motion of the needle, jump foot, and shuttle hook is accomplished by use of three (3) fixed cams and a rack and pinion drive for the shuttle hook.
The primary hook drive cam is located on the back side of the top cam shaft. The precise design of the primary hook drive cam governs the motion of the rack and pinion spring-loaded shuttle hook system. The hook picks up the thread on a return spring action. The cam pushes down against a nylon roller located at the top of the rack, pushing against the spring-loaded rack and pinion. The shuttle hook backs up when the hook shaft drive gear turns, driven down by the gear rack by pressure from the return spring. As the cam turns forward, its shape allows the rack to spring up suddenly, allowing the shuttle hook to move rapidly forward, catching thread off the needle at a point when the needle has risen 3/16″ from the lowest point of its travel.
The shuttle hook continues its rapid movement carrying the thread around the shuttle and bobbin threads to a point beyond 180 degrees so that the needle thread easily clears the entire shuttle assembly.
The primary hook drive cam then allows the gear rack to push down slightly, positioning the finger of the hook drive back to the 180 degree position, setting the hook driver finger and the heel of the shuttle hook in the vertical (“12:00 O′Clock”) position, thus allowing the easy escape of the needle thread through the gap between the hook driver finger and the heel of the shuttle hook. The cam allows the assembly to pause in this position until the needle bar can travel to its highest point, with the needle bar being utilized as the thread takeup and pulling the bobbin thread with it into the material being sewn.
An alternative cam can be utilized which does not kick the shuttle hook back to the 180 degree position, and the thread release point remains beyond the 180 degree position. The needle foot cam is located on the cam shaft at the front of the machine. The needle bar is driven down by the action of the link driver and the pin, which is positioned on the needle feed cam and timed to coincide with the movement for the needle feed action.
Movement is sequentially:
Examination of the device in light of the foregoing disclosure is respectfully requested.
