Torque transmission belt means

A torque transmission belt means which is extended between a driving pulley and a driven pulley for transmitting a driving force from the driving pulley to the driven pulley. The torque transmission belt means comprises a plurality of ring-shaped metallic strips which are superimposed on each other, and two kinds of blocks which are arranged along the metallic strips so as to be shiftably engaged therewith. Only one kind of blocks are contacted with said pulleys and the other kind of blocks are bevelled on opposed surfaces facing to the direction of the movement so that they can tilt with respect to one kind of blocks when they are entrained around the pulleys.

BACKGROUND OF THE PRESENT INVENTION 
The present invention relates to a torque transmission belt which extends 
around a drive pulley and a driven pulley for transmitting a driving force 
from the drive pulley in the driving side to the driven pulley. 
Conventionally, such a transmission belt comprises a plurality of stacked 
ring-shaped metallic strips and a series of blocks which are shiftably 
engaged by the metallic strips. U.S. Pat. No. 3,720,113 discloses an 
example of such a conventional transmission belt. In the transmission belt 
of U.S. Pat. No. 3,720,113, one or both sides of each of the blocks is 
bevelled transversely to the direction of movement so that the blocks can 
tilt with respect to each other when they pass around pulleys. The 
remaining sides of each of the blocks are inclined so as to coincide with 
the angle of inclination of the pulleys. 
One object of the present invention is to provide an improved torque 
transmission belt of the above described type. 
Another object of the present invention is to provide a torque transmission 
belt of light weight. 
A further object of the present invention is to provide a torque 
transmission belt which prevents excessive noise from being generated 
during the operation thereof. 
A still further object of the present invention is to provide a torque 
transmission belt which can be produced with ease.

DETAILED DESCRIPTION 
In FIG. 1, a drive pulley 1 is connected to a shaft 4, such as that of an 
engine. Thus, the pulley 1 is rotated by the driving force of the engine. 
The rotation of the pulley 1 is transmitted to drive a pulley 2 through a 
torque transmission belt 3 so that pulley 2 and an associated operating 
shaft 5 of auxiliary machinery, such as a compressor, an alternator or an 
air pump, are rotated. 
The torque transmission belt 3 consists of a series of blocks 7 and 8, 
which are alternately arranged with respect to each other and rings 6 made 
of metallic material having excellent bending and tensile strength. The 
series of blocks are linked together by the rings 6. 
As shown in FIG. 2, each ring 6 comprises three superimposed metal strips 
61, 62 and 63 so as to improve the tensile strength of the ring. 
The block 7 (hereinafter called "main block") is made of material having 
high strength, such as tool steel. As shown in FIGS. 3 and 4, in both 
sides of each of the main blocks 7, grooves 73 are provided between a base 
portion 72 and a head portion 74. A ring 6, composed of the metal strips 
61, 62 and 63 is slidably inserted within each of the grooves 73. 
Opposed side surfaces 75 of the base portion 72 of the main block 7 
extending in the direction of the movement of the rings 6 are formed 
parallel to one another. The remaining opposed side surfaces 71 of portion 
72 are inclined in such a manner as to reduce the distance therebetween on 
the inner surface of the belt. 
The inclined side surfaces 71 contact inclined surfaces 11 which form a 
V-shaped groove in the pulley 1, as shown in FIG. 7, and inclined surfaces 
(not shown) which form a corresponding V-shaped groove in pulley 2. 
In the secondary blocks 8, grooves 83 are provided between a base portion 
82 and a head portion 84 for receiving the rings 6. The grooves 83 have 
the same shape as grooves 73. 
Opposed side surfaces 85 of the base portion 82 of each of the secondary 
blocks 8 extending transversely to the moving direction are inclined in 
such a manner that the distance therebetween is reduced on the inner 
surface of the belt. By so inclining the side surfaces 85 of the secondary 
blocks 8, the main blocks 7 and the secondary blocks 8 can tilt with 
respect to one another when they pass around the pulleys 1 and 2. 
The remaining opposed side surfaces 81 of each base portion 82 of block 8 
are formed parallel to one another. 
The width L of the base portion 82 of the secondary block 8 is formed 
slightly shorter than the width l of the base end of portion 72 of the 
main block 7. 
Therefore, the side surfaces 81 of blocks 8 do not contact the inclined 
surfaces of the V-shaped grooves of the pulleys 1 and 2. 
The torque transmission belt 3 just described extends between the drive 
pulley 1 and the driven pulley 2. Accordingly, rotation of pulley 1 is 
transmitted the pulley 2 through the main blocks 7, the secondary blocks 8 
and the rings 6. 
By forming the main blocks 7 and the secondary blocks 8 as described above, 
the torque transmission belt of the present invention has following 
operation effects: 
(1) Since the secondary blocks 8 do not contact the inclined surfaces of 
pulleys 1 and the 2, only the main blocks 7 are used as the means of 
transmitting torque from pulley 1 to pulley 2. Consequently, the secondary 
blocks 8 are not required to have such a high strength as the main blocks 
7. 
Therefore, the secondary blocks 8 can be made of non-metallic material 
having excellent compression resistance, such as synthetic resin, carbon 
graphite, synthetic resin containing carbon graphite fibers, and hard 
rubber so that the weight of the torque transmission belt can be reduced. 
As a result, the torque transmission belt of the present invention can be 
effectively applied to pulleys which rotate at high speed. 
(2) Since the secondary blocks 8 can be made of synthetic resin or the like 
as described above, noise occurring when the metallic main blocks 7 and 
the secondary blocks 8 contact one another during the rotation of the 
torque transmission belt becomes small. 
As a result, the torque transmission belt operates silently. 
(3) The main blocks 7 can be easily made of metal by forming inclined 
surfaces on the opposed side surfaces 71 only. 
FIG. 8 to FIG. 11 illustrate a modified embodiment of the present 
invention. 
As shown in FIGS. 8 and 10, grooves 73 and 83 are perforated in the upper 
portions of the main blocks 7 and secondary blocks 8, respectively, for 
receiving the metal strips 61, 62 and 63 of a ring 6. 
The other constructional features of blocks 7 and 8 of this modified 
embodiment are similar to those of the previously described embodiment, 
and the same operational effects are achieved. 
With a torque transmission belt according to the present invention, it is 
not always required that the spaced sides of blocks 8 be parallel to one 
another. If they do not contact the surfaces of the pulleys 1 and 2, they 
can be shaped in any other form. 
Furthermore, the main blocks 7 can be made of material other than tool 
steel if it has the sufficient strength and abrasion resistance required 
in torque transmitting means of this type. 
The secondary blocks 8 also can be made of materials other than described 
above provided it is lighter than that of the main block 7 and has 
sufficient compression resistance so as to be resistant to the pressing 
forces applied from the ring(s) 6 and the main block 7.