The present invention generally relates to a ripsaw stabilizing bar and a method for creating a glue-line quality ripsaw cut. In order to maintain an accurate straight line cut through a ripsaw the product, typically lumber, must be held tightly as it passes through the ripsaw. This process can be a challenge due to the fact that as the product is cut, there is a natural relief of the stresses in the product, typically wood, that causes the wood to bend and move or otherwise actuate away or into the saw blade(s). This causes the wood edges to be shaved by the saw blades or to be cut inaccurately. As a result, the cut product exhibits non-flat edges that have to be planed in a wood or other product planer or moulder to make a smooth glue-line cut.
Currently, ripsaw manufacturers either reluctantly tolerate these jagged ripsawed cuts or typically use some sort of sacrificial material in the area of the saw blades to apply downward force to prevent the wood from bending in the area of the saw blades. However, since this material is repeatedly cut by the saw blade(s) of the ripsaw, it inevitably deteriorates and loses functionality as a means to apply force to the wood. The sacrificed material must be periodically replaced, requiring large amounts of down time for the ripsaw.
The present invention generally relates to a ripsaw stabilizing device that allows the complete system employing the device to cut a glue line quality cut(s) when used in connection with a ripsaw. A glue line quality cut is generally any cut that, when two cut pieces are glued together is so smooth and so straight as to not have a gap, in general this means that the hollow joint gap at mid-length of two freshly sawed forty inch long pieces is 0.005 inches or less, more preferably 0.004 inches or less. In an embodiment of the present invention this is achieved by minimizing the transition area from the upper pressure rollers of the ripsaw that carry the work before and after the wood passes through the blade to the ripsaw stabilizing device, which provides downward pressure on the wood while it is being cut. Both the force from the rollers and the force from the ripsaw stabilizing device stabilize the wood. As a result, the cut made by the saw blade(s) of the ripsaw is glue-line quality without down time for replacement of disposable materials and/or the need to further process the wood, such as being planed in a planer or moulder.
One aspect of the present invention includes a ripsaw stabilizing device that has a moveable carrier arm subassembly, a hold-down subassembly, a hold-down support engaged to the moveable carrier arm subassembly and a force applying subassembly engaged to the hold-down subassembly and the hold-down support that applies downward force such that downward force is applied to a piece of material being cut on both sides of the blade as the material travels through the saw. Another aspect of the present invention includes a method for making a glue-line quality cut without further processing of the material being cut and without the use of a sacrificial hold-down material. Yet another aspect of the present invention includes a ripsaw including one or more ripsaw stabilizing devices of the present invention.
These and other features, advantages and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims and appended drawings.
The present invention generally relates to a ripsaw stabilizing device 10 that generally includes a moveable carrier arm subassembly 12, a hold-down subassembly 14 and a force applying subassembly 16.
The moveable carrier arm subassembly 12 of the ripsaw stabilizing device 10 typically includes an aperture 20 for attachment of the moveable carrier arm 22 to a servo arm 21 of the ripsaw. A ripsaw may include multiple ripsaw stabilizing devices and their accompanying ripsaw blades mounted on one or more servo arms. The use of multiple servo arms allows for independent movement of multiple blades to minimize waste in cutting wood. The blades can be positioned independently to, for example, cut out imperfections in the wood such as knots, wane, splits, pitch pockets or bark pockets. The servo arm may be controlled by a computer linked to one or more other computers or a computer network for adjusting the location of the cut by the saw blade of the ripsaw. Jack screws 24 are used to adjust the angle of the bottom surface 25 of the entire ripsaw stabilizing device. This allows for fine adjustments to the angle of the entire ripsaw stabilizing device and facilitates proper alignment with the feed surface of the ripsaw that carries the wood. This allows the operator to, if desired, ensure that the device is at least substantially if not exactly parallel with the surface carrying the incoming material (wood) to be cut by the blade. The moveable carrier arm 22 carries the hold-down subassembly 14 in a channel 26 along its substantially parallel downwardly extending sides 28. The channel 26 on the moveable carrier arm 22 allows for vertical movement and allows movement laterally of the entire hold-down device on the saw blade shaft to adjust to different cut dimensions. The upper portion 27 of the moveable carrier arm may be of multiple shapes to facilitate mounting on multiple servo arms 21 in a manner that allows for independent movement of the ripsaw stabilizing device(s) mounted on different servo arms. Each servo arm 21 may be engaged to multiple ripsaw stabilizing devices. A computer or operator may adjust the location of from typically 2-4, 5 or 6 blades. In this manner, maximum efficiency in avoiding waste materials (e.g. avoiding and cutting out knotted portions of the lumber, wane, splits, pitch pockets or bark pockets being cut) may be obtained. The upper portion of the moveable carrier arm 22 is typically about 15 mm thick. Jack screws 86 and lock bolts 74 are used (in conjunction with locknuts 88) to adjust the angle of the bottom surface 25 of the entire ripsaw stabilizing device.
The moveable carrier arm further includes a bushing and bearing retaining plate 30 engaged to the moveable carrier arm on both sides. Typically the bushing and bearing retaining plates are engaged to the carrier arm 22 using plate bolts 32. The bushing and bearing retaining plates 30 retain the blade side bushing 34 and the rear side bushing 36 in position in the carrier arm 22. The bushing on the blade side is typically about 66% of the total thickness of the blade side and the rear side bushings. The additional dimension of the blade side bushing is utilized to carry the blade 38. The amount of the bushing holding the bearings 40 is typically the same on each side or approximately the same on each side. The bushings are typically retained using bushing bolts 42 positioned around the bushings as shown in
The bearing 48 and races 50 are shown in
The blade side bushing and rear side bushing are typically made of brass or other metal softer than steel. The bushings are preferably produced from brass because the brass will wear out prior to the steel components of the main portion of the ripsaw stabilizing device. As a result, the bushings wear and the remainder of the ripsaw stabilizing device has a long life. The bushings are less expensive than the entire hold-down device and more easily replaceable than an entire hold-down device.
The hold-down assembly 14 of the ripsaw stabilizing device generally includes a front, blade side generally U-shaped hold-down bracket 56 and a rear side generally U-shaped hold-down bracket 58. The front/blade side generally U-shaped hold-down bracket 56 and the rear side generally U-shaped hold-down bracket 58 are adjoined by a generally C-shaped channel forming bracket 60. The generally U-shaped hold-down brackets and the C-shaped channel forming brackets are typically engaged to one another or held together at each connection point by one or more welds. As shown in
The assembly formed by the generally U-shaped hold-down brackets and the C-shaped channel forming bracket preferably engages the moveable carrier arm. Typically they are engaged using a hold-down support bar 62 with a force applying subassembly 16 therebetween.
The force applying subassembly 16 typically engages the top surface or top portion of the rear side generally U-shaped hold-down bracket 58. This attachment is generally shown in
The hold-down support bar 62 is typically engaged to the moveable carrier arm via support bar bolts 74 and washers 76. The location of the support bar bolts 74 can be varied along height adjustment channels 78. The support bar bolts may be positioned in one of one or more pairs of apertures (82a,b or 84a,b) (see
The above description is considered that of the preferred embodiment only. Modifications of the invention will occur to those skilled in the art and to those who make or use the invention. Therefore, it is understood that the embodiment shown in the drawings and described above is merely for illustrative purposes and not intended to limit the scope of the invention, which is defined by the following claims as interpreted according to the principles of patent law, including the doctrine of equivalents.
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