Abrading – Abrading process
Reexamination Certificate
1999-05-28
2001-04-24
Banks, Derris H. (Department: 3723)
Abrading
Abrading process
C451S188000
Reexamination Certificate
active
06220932
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to power transmission belts and, more particularly, to a method of producing a double-sided power transmission belt, or belt sleeve from which one or more power transmission belts can be formed, having at least one load carrying cord embedded therein. The invention is also directed to a double-sided power transmission belt or belt sleeve made according to the method.
2. Background Art
One known manner of forming double-sided, ribbed belts is shown in JP-A7-124856. There is disclosed therein a belt sleeve, having a load carrying cord embedded in a cushion rubber layer, trained around pulleys having the same diameter. Multiple ribs, with grooves therebetween, are formed by a grinding wheel on one surface of the belt sleeve as it is moved around the pulleys. The belt sleeve is then turned inside out and again trained around the pulleys to form, through the grinding wheel, ribs, and grooves therebetween, on the other side of the sleeve. To prevent lateral shifting of the belt sleeve during formation of the ribs on the other side, it is known to use a cartridge, on one or both of the pulleys, with a shape complementary to the ribs and grooves formed on the one side of the belt sleeve. This permits an accurate, desired, lateral alignment between the ribs on the opposite surfaces of the belt sleeve to be established.
In a conventional forming process, the belt sleeve is ground on opposite sides without consideration of the position of the load carrying cords and a possible discrepancy in the location of the load carrying cords from that intended between the inside and outside of the belt sleeve. While accurate lateral alignment between the ribs on the oppositely facing surfaces may be established, the load carrying cords in the resulting belt may be closer to one surface than the other, rather than precisely centered therebetween as intended. This condition may cause an appreciable variation in operating characteristics with the belt operated in normal and reverse rotational modes. The pulley outer circumference (POC) may vary with the belt trained around a pair of pulleys and rotated thereabout. As a result, the desired rotational ratio between pulleys on which the belt is mounted may vary significantly.
SUMMARY OF THE INVENTION
The invention is directed to a method of producing a double-sided belt structure from an endless body having a length, a first surface, a second surface, at least one load carrying cord embedded in the body with a lengthwise center and extending along the length of the body between the first and second surfaces of the body, and a thickness between the first and second surfaces of the body. The method includes the steps of moving the body in a controlled endless path around at least a first pulley with the second surface of the body outside of the first surface of the body; while the body is moving in the endless path, a) predetermining a center position of the center of at least one load carrying cord between the first and second surfaces of the body, b) determining a grinding value for the first surface of the body based on the center position of the center of the at least one load carrying cord, and c) determining a grinding value for the second surface of the body based on the center position of the center of the at least one load carrying cord; grinding the second surface of the body based upon the determined grinding value for the second surface of the body; and grinding the first surface of the body based upon the determined grinding value for the first surface of the body.
It is one objective of the present invention to allow accurate location of the at least one load carrying cord between the oppositely facing surfaces of a belt structure between which the belt thickness is defined. In the event that the load carrying cord is inadvertently located closer to one surface of the belt sleeve than the other, an accommodation can be made so that the resulting belt structure has the desired relationship between the at least one load carrying cord and the oppositely facing surfaces of the belt structure.
The step of moving the body in a controlled path around at least a first pulley may involve moving the body in the controlled path around the first pulley and a second pulley, having a diameter that is different than the diameter of the first pulley, through rotation of the first and second pulleys.
The second surface may be ground to form one rib or a plurality of ribs.
The first surface may be ground to form one rib or a plurality of ribs.
The step of determining the grinding values for the first and second surfaces may involve determining the grinding values so that the center of the at least one load carrying cord is spaced equally from free end surfaces of the ribs on the first and second sides of the belt structure.
The step of predetermining a center position of the center of the at least one load carrying cord may involve predetermining a center position of the center of the at least one load carrying cord based on a ratio of rotational velocities of the first and second pulleys.
The step of determining a grinding value (y
1
) for the second surface may involve determining a grinding value according to the following equation:
y
1
=2w−(&agr;+&bgr;)
where:
a) 2w is the thickness of the body before grinding;
b) &agr; is the center position of the center of the at least one load carrying cord; and
c) 2&bgr; is the thickness of the double-sided belt product.
The step of determining a grinding value (y
2
) for the first surface may involve determining a grinding value for the first surface according to the following equation:
y
2
=&agr;−&bgr;
where:
a) &agr; is the center position of the center of the at least one load carrying cord; and
b) &bgr; is equal to ½ the thickness of the double-sided belt product.
The step of predetermining a center position (&agr;) of the center of the at least one load carrying cord may involve predetermining a center position of the center of the at least one load carrying cord according to the following equation:
&agr;=(&ohgr;
1
·
A
−&ohgr;
2
·
B
)/[2 ·(&ohgr;
2
−&ohgr;
1
)]
where:
a) A is the diameter of the first pulley;
b) B is the diameter of the second pulley that is less than the diameter of the first pulley;
c) &ohgr;
2
is the rotational velocity of the first pulley; and
d) &ohgr;
1
is the rotational velocity of the second pulley.
The method may include the step of moving the body in a controlled endless path around a pulley with the first surface of the body outside of the second surface of the body while grinding the first surface of the body.
The method may involve removing foreign material from the body as at least one of the first and second surfaces of the body is ground.
The foreign material may be removed by brushing the body and/or by generating vacuum adjacent to the body to draw foreign material away from the body.
The method may include the step of sensing the rotational velocities of the first and second pulleys and producing a signal indicative of the rotational velocities of the first and second pulleys. The step of determining the grinding value for the second surface of the body may involve processing the signal through a controller to determine the grinding value for the second surface.
The method may include controlling a grinding element that grinds the second surface through the controller.
The method may further include the step of causing the controller to automatically stop grinding of the second surface once the grinding reaches the grinding value for the second surface.
The invention may further include the step of causing the controller to initiate operation of at least one of a brush and a vacuum source to remove foreign material from the body as at least one of the first and second surfaces is ground.
The invention is also directed to a double-sided belt structure made according to the above method. The double-sided belt structure may be a power
Banks Derris H.
Mitsuboshi Belting Ltd.
Wood Phillips VanSanten Clark & Mortimer
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