Abrading – Machine – Rotary tool
Reexamination Certificate
1998-12-17
2001-04-10
Jones, David (Department: 3725)
Abrading
Machine
Rotary tool
C451S024000, C451S051000, C451S188000, C451S194000, C451S541000
Reexamination Certificate
active
06213850
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and apparatus for producing a raw edge belt.
2. Description of the Related Art
A raw edge belt is a ring-shaped power transmission belt a section of which is an inverted trapezoid (or V-form).
FIG. 3
is a perspective view of a belt showing a section and part thereof. As shown in
FIG. 3
, the belt is provided with an upper rubber layer
31
, tensile members
32
, and a lower rubber layer
33
.
FIG. 4
shows the production procedure of a belt. The production procedure is 1) to build these constituent materials, in this order, as cylindrical layers, starting from the inner side, then vulcanize the built-up work to form a sleeve (vulcanized sleeve, of which section is shown in
FIG. 4
(
a
)); 2) to slice or section the sleeve into pieces of a desired width (belt width) along the dotted lines x to get ring-shaped belts of which section is rectangular (called square-cut belts and shown in
FIG. 4
(
b
)); and 3) to cut these square-cut belts obliquely along the dotted lines y to get raw edge belts of which section is a V-form (
FIG. 4
(
c
)). The present invention relates to steps for cutting the square-cut belts into belts of a V-form section to get raw edge belts.
For example, examined Japanese Provisional Patent Publication No. HEI 5-28978 discloses “a production method wherein a vulcanized sleeve is put between two spindles, the sleeve is made to run circularly, a group of integrated grinding wheels, comprising a plurality of grindstone discs of which peripheral section is a V-form, is kept rotated and pressed against the peripheral surface of the vulcanized sleeve to cut into it and grind plural V-shaped grooves, and positioning members are fit into the V-grooves to cut the sleeve into individual raw edge V-belts.”
Another method for producing a raw edge V-belt is, first, to square-cut (this means slicing or sectioning a sleeve into rings having a rectangular section) a vulcanized sleeve into pieces of a desired belt width, then to grind and polish a belt, one at a time, to change its section into a V-form. As for a production apparatus for grinding a belt into a V-section belt, Japanese Provisional Patent Publication No. HEI 8-164568 discloses a V-section cutting apparatus wherein two milling cutters are arranged so that their cutting edges have angles of inclination for grinding the sides of a belt into a V-section.
The method disclosed by the above-mentioned Japanese Patent Publication No. HEI 5-28978 tends to induce meandering since a wide vulcanized sleeve is made to run circularly over two spindles. Moreover, as many grinding wheels are made to cut into the sleeve concurrently to form V-grooves, the sectional configuration may be distorted by compression, resulting in defective configurations (dents in the inclined sides or displacement). As for the method wherein one square-cut belt is polished into a V-section belt at a time, the productivity is low, resulting in higher cost. As for the milling system with cutters, the life of the cutters is short, posing problems of cutter replacement time and higher cost.
The present invention is intended to solve the above-mentioned quality problems caused by meandering, displacement, etc., and at the same time, to solve the problems of longer working time and higher cost of the method of finishing one square-cut belt at a time.
SUMMARY OF THE INVENTION
A raw edge belt is produced according to the method of the present invention by placing plural square-cut ring-shaped belts across a main spindle roller and a tension roller, running the belts circularly, and polishing the belts to have a substantially V-shaped section. The ring-shaped belts are roughly ground on the main spindle roller by a rough grindstone having V-forms in its peripheral section into belts with a substantially V-shaped section, and in succession, the roughly-ground ring-shaped belts are subjected to finish polishing with a finish grindstone.
The method of the present invention grinds belts with a higher efficiency than a method of grinding one belt at a time, because a plural number of square-cut ring-shaped belts are ground simultaneously. Grinding with a better efficiency is realized by, first, roughly grinding the square-cut ring-shaped belts with a rough grindstone (of which grain size is larger) having V-forms in its peripheral section to change the belts' sections into a substantially V-form. In succession, the roughly-ground ring-shaped belts are subjected to finish polishing with a finish grindstone that is formed similarly to the rough grindstone and has a smaller grain size. In this way, the ring-shaped belts are never subjected to excessive forces, and are free of strains and displacement. As a result, finishing with a higher dimensional accuracy can be accomplished with high efficiency.
In accordance with another aspect of the invention, an apparatus for producing raw edge belts is provided. A main spindle roller is mounted horizontally and designed to hold square-cut ring-shaped belts, a tension roller is located beneath the main spindle roller, being parallel with said main spindle roller and being installed so that it can be raised or lowered, a first rotary grindstone being capable of coming close to or moving away from said main spindle roller and is mounted on the upstream side of the direction of rotation of said main spindle roller, and a second rotary grindstone being capable of coming close to or moving away from said main spindle roller and being mounted on the downstream side of the direction of rotation of said main spindle roller.
As the main spindle roller according to the present invention is mounted horizontally, ring-shaped belts can be easily put on the main spindle roller. When the tension roller, which may be raised or lowered, is raised, ring-shaped belts can be easily put across said main spindle roller and the tension roller or removed from them, and when the tension roller is lowered, a desired tension is given to the ring-shaped belts being held across the rollers to prevent the belts from slipping over the main spindle roller. Moreover, as the tension roller is mounted parallel to the main spindle shaft, the ring-shaped belts will not meander when the belts are made to run circularly.
The first rotary grindstone can be moved close to or away from the main spindle roller. The first rotary grindstone, being rotated, is made to come close to the main spindle roller and contact the ring-shaped belts being put on the main spindle roller and being made to run circularly so as to roughly grind the belts. Replacement of ring-shaped belts is made easier by moving the first rotary grindstone away from the ring-shaped belts. Moreover, the resistance against the ring-shaped belts can be adjusted by adjusting the approaching speed, thus a design wherein ring-shaped belts will not be displaced on the main spindle roller can be made. The second rotary grindstone is mounted on the downstream side of the direction of rotation of the main spindle roller, and with this arrangement, the ring-shaped belts, that have been roughly ground by the first rotary grindstone, can be finish-polished continuously without any replacement. The V-form of the ring-shaped belts that have been substantially formed by the first rotary grindstone is accurately finished into the designed V-form.
In accordance with another aspect of the invention, the tension roller of the apparatus is provided with ribs or flanges for fixing plural ring-shaped belts at the ends thereof. These ribs keep the individual sectioned square-cut belts as one body while these belts are circulated across the main spindle roller and the tension roller, prevent the belts from meandering, and at the same time enable grinding and polishing.
In accordance with another aspect of the invention, the first rotary grindstone is a rough grindstone comprising an assembly of grinding wheels of which peripheral section is a V-form, and the second rotary grindstone is a finish grindstone comprising an
Hasegawa Noboru
Hashino Seiji
Bando Kagaku Kabushiki Kaisha
Jones David
Kueffner Friedrich
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