Patent Application
20140260873
1. Field of the Invention
The present invention relates generally to a band saw machine, and more specifically to a saw blade tension adjusting apparatus for a band saw machine that can provide high structural strength and ensure stable operation.
2. Description of the Related Art
Before using a band saw machine in cutting a workpiece, an operator needs to adjust the tension of a saw blade in advance for maintaining the cutting stability and extending the working life of the saw blade. As far as prior art is concerned, Taiwan Patent No. 491118 discloses a slide base and a wheel bracket connected with the slide base so as to be driven to move upwards or downwards by the actuation of the slide base. By this way, a driven wheel rotatably connected with the wheel bracket can be moved along with the wheel bracket for adjusting the tension of the saw blade running around the driven wheel.
However, the slide base of the aforesaid Taiwan patent has low structural strength because it is made of sheet metal with an inverted U-shaped section. Furthermore, an excessive gap exists between the inverted U-shaped slide base and the wheel bracket, such that vibrations may be generated at the driven wheel when the wheel bracket is moved downwards and displacements of the driven wheel may occur when the wheel bracket is moved upwards. Thus, it is desired to provide an improved saw blade tension adjusting apparatus for the band saw machine.
It is one objective of the present invention to provide a saw blade tension adjusting apparatus for a band saw machine, which has the advantage of high structural strength and stable operation.
To achieve this objective of the present invention, the saw blade tension adjusting apparatus comprises a retaining base, a movable base having two opposite sliding shafts slidably inserted into the retaining base, a top plate connected with top ends of the sliding shafts, a bottom plate connected with bottom ends of the sliding shafts, and a wheel bracket mounted to the sliding shafts and located between the top and bottom plates. A control unit includes a handle and a cam connected with the handle such that the cam is driven by the handle to rotate relative to the movable base between a tightening position and a loosening position. When the cam is located at the tightening position, a large diameter portion of the cam pushes against the top plate of the movable base such that the movable base is moved upwards to tighten the tension of a saw blade. When the cam is located at the loosening position, the movable base is moved downwards to allow the top plate of the movable base to lean on a small diameter portion of the cam for releasing the tension of the saw blade.
Preferably, a fine-tuning unit is provided by the present invention, including a support plate slidably disposed between the sliding shafts of the movable base and located between the wheel bracket and the bottom plate of the movable base, a spiral spring disposed between the wheel bracket of the movable base and the support plate, a nut mounted on the bottom plate of the movable base, and a screw rod rotatably inserted into the bottom plate of the movable base, the support plate, and the spiral spring and having a threaded portion threaded with the nut. Thus, the movable base can be driven to move slightly by the rotation of the screw rod.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:
As shown in
The retaining base 30 is fastened to the upper case 11 and provided with a first block 32 and two opposite second blocks 34 fastened to two sides of the first block 32.
The movable base 40 includes two opposite sliding shafts 41 slidably inserted into the first block 32 of the retaining base 30 such that the sliding shafts 41 are movable upwards and downwards relative to the retaining base 30, a top plate 42 connected with top ends of the sliding shafts 41 so as to be moved along with the sliding shafts 41, a bottom plate 43 connected with bottom ends of the sliding shafts 41 so as to be moved along with the sliding shafts 41, and a Wheel bracket 44 mounted on the sliding shafts 41 and located between the top and bottom plates 42 and 43 for connection of the driven wheel 13. By this way, the driven wheel 13 can be driven by the movement of the movable base 40 to move upwards and downwards relative to the retaining base 30.
The control unit 50 includes a handle 51 and a cam 52 fixedly sleeved on a rotating shaft 512 of the handle 51 and having a large diameter portion 522 and a small diameter portion 524 with a leaning plane 526, as shown in
When disassembling the saw blade 15, as shown in
On the contrary, when assembling the saw blade 15, the operator pushes upwards the handle 51 to force the cam 52 to be rotated to a tightening position P2, as shown in
Besides, a fine-tuning unit 60 is provided by the present invention for adjusting the saw blade 15 to a suitable tension, including a support plate 61 slidably disposed between the sliding shafts 41 of the movable base 40 and located between the Wheel bracket 44 and the bottom plate 43, a spiral spring 62 disposed between the wheel bracket 44 of the movable base 40 and the support plate 61, a nut 63 mounted on the bottom plate 43 of the movable base 40, and a screw rod 64 rotatably inserted into the bottom plate 43 of the movable base 40, the support plate 61, and the spiral spring 62, and having a threaded portion 642 threaded with the nut 63. A thrust bearing 65 is mounted on the screw rod 64 and abutted against the bottom side of the support plate 61, and a handwheel 66 is connected with one end of the screw rod 64 and exposed out of the upper case 11 for driving the rotation of the screw rod 64.
When the screw rod 64 is rotated by the actuation of the handwheel 66, as shown in
To deserve to be mentioned, two limiting rings 45 are fixedly sleeved on the sliding shafts 41 and adjacent to the top side of the wheel bracket 42 for restricting the upward movement of the wheel bracket 42. Furthermore, a tension meter 46 is pivotally connected with the upper case 11 and provided with a slot 462 for insertion of a protrusion 612 of the support plate 61, such that the tension meter 46 is pivotable along with the movement of the support plate 61 for measuring the tension of the saw blade 15, and the measured tension can be shown by a scale (not shown).
Above all, the tension of the saw blade 15 is adjusted by up-and-down movement of the movable base 40 through the two sliding shafts 41, and therefore the claimed invention has higher structural strength and provides more stable operation when compared with the prior art, thereby achieving the purpose of the present invention.
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
