Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
2000-05-09
2002-12-03
Vo, Peter (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C029S594000, C029S609100, C029S592100, C029S893340, C381S398000, C381S405000
Reexamination Certificate
active
06487771
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing speaker bottom yoke, which shortens the manufacturing time, increases production capacity, enhances product quality and beautifies the appearance of the product. This method is especially applicable to the base seat of a speaker.
As shown in
FIG. 5
, a conventional speaker bottom yoke is made of an iron bar blank material A with smaller diameter. The iron bar blank material A is first punched into a bottle shape B. Then the blank material is secondarily punched to expand the head end thereof into a mushroom head shape C. At this time, the iron bar blank material with mushroom head end has almost reached the forging ratio of the material. Therefore, for further forging the material into the necessary bottom yoke with specific dimension, it is necessary to anneal the material. Otherwise, the material will be torn apart. In the annealing procedure of metal material, it is necessary to remove the iron bar blank material A from the punching mold. After the annealing procedure, the iron bar blank material A is again put back into the mold for further processing. The above conventional annealing procedure includes multiple complicated steps such as skin removing and sand spraying. After the annealed semi-product is again placed into the punching mold cavity, some shortcomings may take place, such as inaccurate mating and prolonged manufacturing time.
The mushroom head end must be processed into a suitable thickness as necessary. The body of the bottom yoke is continuously punched and forged into a necessary precision of dimension to form a bottom yoke specifically for speaker.
During the manufacturing procedure of the bottom yoke, the large-sized bottom disc is forged in such a manner that the small diameter iron bar is continuously pressed to form a large-sized bottom disc. Therefore, the density of the iron bar is changed from low density into compact density. Therefore, after this step, an annealing step is required to soften the tissue of the iron bar and then the successive manufacturing step can be performed. In case the annealing step is omitted and the too dense iron bar blank material is further forged, the forging mold is very likely to damage. Also, in case the forging ratio of the product has is too high, the material may be torn apart to form defective product. Therefore, it is necessary to first anneal the material and remove the iron bar blank material from the mold. After annealed, the material is again moved back into the mold for further forging. Such procedure is quite time-consuming and laborious. As a result, the manufacturing time is prolonged and the production capacity is reduced and thus the cost for labor is increased. In this field, the production efficiency of working time occupies almost 30~40% of the manufacturing cost.
SUMMARY OF THE INVENTION
It is therefore a primary object of the present invention to provide a method for manufacturing speaker bottom yoke, by which the operation is unified and the annealing step is unnecessary and it is unnecessary to remove the forged blank material from the mold. This method shortens the manufacturing time and increases production capacity.
It is a further object of the present invention to provide the above manufacturing method by which the appearance of the speaker bottom yoke is beautified.
According to the above objects, the method for manufacturing speaker bottom yoke of the present invention includes steps of: 1. calculating product weight according to required dimension; 2. cutting off a blank material with the calculated weight from steel bar (material bar), which blank material can be further planed; 3. performing first time forging to forge one end of the blank material into a stem section with reduced diameter, which stem section can be simultaneously formed with a sink in accordance with the required shape and dimension of the bottom yoke; 4. performing second time forging to forge the other end of the blank material into a bottom disc with larger diameter; and 5. performing third time forging to further forge the bottom disc of the blank material into a predetermined dimension.
In the above forging procedure, the diameter of the blank material is forged from large dimension into small dimension and the bottom disc is forged at two times into a specific dimension. Therefore, the blank material will not have too high density over the forging ratio and thus the annealing operation is unnecessary. Therefore, it is unnecessary to remove the blank material from the mold and the operation can be unified to shorten the manufacturing time and mass-produce the products.
The present invention can be best understood through the following description and accompanying drawings wherein:
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Trinh Minh
Varndell & Varndell PLLC
Vo Peter
LandOfFree
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