A belt for transmitting power from a cogged driving member to a cogged driven member such as a pair of wheel sprockets is described. The belt has inflexible teeth spaced along the direction of its travel. Each of the teeth has a longitudinal axis transverse to the direction of belt travel. The belt also includes substantially inextensible fasts spaced transversely to the direction of belt travel. The fasts extend in the direction of belt travel adjacent to the teeth and are looped around preselected numbers of the teeth

Bahiman, H.

English

NASA Technical Reports Server

__ United States Patent 1191 
Bahiman 
P11 4,215,590 
[451 Aug. 5,1980 
BELT FOR TRANSMITTING POWER FROM 
A COGGED DRIVING MEMBER TO A 
COGGED DRIVEN MEMBER 
Inventor: Hossein Bahiman, Landover Hills, 
Assignee: 
Md. 
The United States of America as 
represented by the Administrator of 
the National Aeronautics and Space 
Administration, Washington, D.C. 
Appl. No.: 943,086 
Filed: Sep. 18, 1978 
Int. C1.2 ........................... F16G l/l& F16G 5/10 
U.S. Cl. .................................... 474/205; 198/847; 
198/848 
Field of Search .................... 74/231 M, 237, 239, 
74/245 S, 250 R, 250 S, 250 C; 198/847, 848, 
849 
References Cited 
U.S. PATENT DOCUMENTS 
3,016,756 1/1962 Jackel ................................ 74/237 X 
3,276,570 10/1966 Hale et al. ............................ 198/848 
3,961,540 6/1976 Harvey ......................... 74/231 M X 
3,973,670 SA976 Spaar ................................. 74/231R 
FOREIGN PATENT DOCUMENTS 
444028 2/1968 Switzerland ............................. 198/848 
Primary Examiner-Leslie Braun 
Assistant Examiner-Conrad Berman 
Attorney, Agent, or Firm-Robert D. Marchant; John R. 
Manning; John 0. Tresansky 
[571 ABSTRACT 
A belt for transmitting power from a cogged driving 
member to a cogged driven member such as a pair of 
wheel sprockets. The belt has inflexible teeth spaced 
along the direction of its travel. Each of the teeth have 
a longitudinal axis transverse to the direction of belt 
travel. The belt also includes substantially inextensible 
fasts spaced transversely to the direction of belt travel. 
The fasts extend in the direction of belt travel adjacent 
to the teeth and are looped around preselected numbers 
198,860 1/1878 Starck .................................... 74/237 Of the teeth. 
277,678 5/1883 Campbell ............................... 74/237 
2,114,181 4/1938 Guba .................................... 198/849 11 Claims, 4 Drawing Figures 
https://ntrs.nasa.gov/search.jsp?R=19800024209 2020-03-21T03:16:06+00:00Z
U.S. Patent Aug. 5, 1980 4,215,590 
4,215,590 
CI 1 
BELT FOR TRANSMITTING POWER FROM A 
COGGED DRIVING MEMBER TO A COGGED 
DRIVEN MEMBER 
ORIGIN OF THE INVENTION 
The invention described herein was made by an em- 
ployee of the United States Government and may be 
manufactured and used by or for the Government for 
governmental purposes without payment of any royal- 
ties thereon or therefor. 
BRIEF SUMMARY OF THE INVENTION 
This invention relates generally to power transmis- 
sion devices and more particularly to belts for transmit- 
ting power from a cogged driving member to a cogged 
driven member. 
Power transmitting belts are known and used in in- 
dustry at an ever increasing rate. These belts are often 
subjected to many types of environmental and opera- 
tional hazards such as extreme cold or heat, radiation 
degradation, longitudinal stretching, fatigue from con- 
stant change of curvature, and wear due to parts engag- 
ing the driving and driven members. Any one or combi- 
nation of these hazards tend to wear and deform the 
belts so that they may prematurely become useless 
thereby requiring frequent replacement. In many situa- 
tions it is virtually impossible to change belts such as 
those used in spacecraft, permanently encased equip- 
ment, equipment used in tunnels and mine shafts, and 
sealed machines. 
There are numerous types of drive belts available 
which are designed to accomplish a desired purpose. 
One such belt used in spacecraft is made of polymer 
fibers to provide tensile strength. The fibers of this belt 
are coated with plastic and form the teeth without any 
reinforcement. Due to the constant change in cuvature 
during operation and being bombarded by solar radia- 
tion the belt undergoes fatigue which causes the plastic 
teeth to crack, deteriorate, and wear so that slippage 
between the teeth and wheel sprockets occur. In addi- 
tion, the fibers tend to stretch which causes the tensile 
stress to substantially subside causing teeth slippage and 
premature breakage of the belt. Other prior art type 
belts are made with longitudinal and transverse fibers to 
give added tensile strength. These fibers are, however, 
still subject to stretching after continued use and the 
Dlastic or matrix formed teeth are subiect to wear and 
5 
10 
15 
20 
25 
30 
35 
40 
45 
deterioration which could cause premature failure of 50 
the belt. 
Briefly, these and other disadvantages are overcome 
by providing a power transmitting belt for connecting a 
cogged driving member to a cogged driven member 
with a plurality of inflexible teeth spaced along the 55 
direction of belt travel. The teeth have a longitudinal 
axis transverse to the direction of travel of the belt. 
Substantially inextensible fasts are spaced transversely 
to the direction of belt travel. These fasts extend in the 
direction of belt travel adjacent to the teeth and are 60 
looped around preselected numbers of the teeth. 
Accordingly, one object of the invention is to pro- 
vide a new and improved belt for transmitting power 
from a cogged driving rotating member to a cogged 
Another object of the present invention is to provide 
a drive belt that is substantially immune to failure when 
subjected to hazardous environmental conditions. 
driven rotating member. . 65 
L 
Still another object of the invention is to provide a 
drive belt that is substantially immune to fatigue and 
cracking. 
A further object of this invention is to provide a drive 
belt that is substantially immune to stretching in the 
direction of belt travel. 
A still further object of the invention is to provide a 
drive belt which is substantially immune to slippage 
around the cogged driving and cogged driven mem- 
bers. 
The above and further objects of the invention will 
appear more fully from the following detailed descrip- 
tion when considered in conjunction with the accompa- 
nying drawings. 
BRIEF DESCRIPTION OF THE DRAWINGS 
In the drawings where like parts are designated by 
the same references. 
FIG. 1 is a side view of the belt for transmitting 
power from a cogged driving member to a cogged 
driven member. 
FIG. 2 is a cross sectional view of the belt taken along 
the lines 11-11 of FIG. 1 showing the cylindrical rod 
and the wires adjacent to and looping the rod, without 
any incapsulating material. 
FIG. 3 is a top view of the belt taken along the lines 
111-111 of FIG. 1 showing the relationship between the 
cylindrical rods and wires, without any incapsulating 
material. 
FIG. 4 is a cross-sectional view of the belt taken 
along the lines IV-IV of FIG. 2 showing the encapsu- 
lating flexible material. 
DESCRIPTION OF THE PREFERRED 
EMBODIMENT 
FIG. 1 illustrates a belt, generally designated by nu- 
meral 10, for transmitting power from a cogged driving 
member 12 to a cogged driven member 14. Members 12 
and 14 may be wheels fixedly mounted on shafts 16 and 
18, respectively. Shaft 16 may be connected to a power 
source (not shown) for rotating driving wheel 12 while 
shaft 18 may be connected to any type of machinery 
(not shown) which is to be turned. Each of wheels 12 
and 14 contain a plurality of cogs or sprockets 20 and 
22, respectively, equidistantly spaced around their re- 
spective peripheries 24 and 26. Belt 10 is preferably of a 
continuous construction and extends around wheels 12 
and 14 in the direction of belt travel indicated by arrows 
28. 
Referring now also to FIGS. 2 and 3, belt 10 includes 
a plurality of inwardly projecting inflexible teeth 30 
which are capable of engaging depressions or spaces 32 
and 34 between cogs 20 and 22, respectively, on wheels 
12 and 14, respectively. The teeth are preferably cylin- 
drical rods having a longitudinal axis 36 which extends 
transversely of the direction of travel of belt 10. Each of 
cylindrical rods 30 is spaced from adjacent cylindrical 
rods 30 in the direction of belt travel by an amount 
substantially equivalent to the spacing of adjacent 
spaces 32 and 34 of wheels 12 and 14 so that as belt 10 
travels around wheels 12 and 14 each cylindrical rod 30 
engages spaces 32 and 34. Preferably, cylindrical rods 
30 extend the width of belt 10. Rods 30 are made from 
any inflexible material so that they will not be subjected 
to fatigue forces that are inherent in teeth that continu- 
ously flex as they travel around wheels 12 and 14. By 
substantially eliminating fatigue on rods 30 they will not 
be subjected to premature wear, cracking, and breakage 
4,215,590 
3 4 
which would cause rods 30 to slip over cogs 20 and 22. M=K(N+ 1)+ 1, if N is equal to 2 and K is equal to 6 
The inflexible material is preferably stainless steel then M is equal to 19 and in the relationship 
which is substantially immune to degradation by solar M=K(N+ 1)- 1, if N is equal to 2 and K is equal to 6 
and other type radiation and other environmental ha- then M is equal to 17. 
zards. As shown in FIG. 4, wires 38 and rods 30 may be 
As clearly shown in FIGS. 2 and 3, belt 10 further encapsulated in a flexible material 44 to reduce any 
includes inextensible fasts or connecting elements 38. wear that may be caused by rods 30 contacting wheels 
Each element 38 is spaced from adjacent elements 38 12 and 14 and to reduce any noise generated by metal to 
transverse to the direction of belt travel and extends as metal contact. It is preferred that material 44 be made 
a continuous entity in the direction of belt travel. Ele- 1o from a flexible substance such as rubber or plastic. 
ments 38 serve to tie rods 30 together to form a continu- Obvious modifications and variations of the disclosed 
ous belt. Elements 38 are made from any inextensible embodiment of the invention are possible in light of the 
material and of any shape as long as it does not stretch above teachings. It is to be understood, therefore, that 
in the direction of belt travel which may result in teeth within the scope of the appended claims, the invention 
slippage, but concurrently is sufficiently flexible to may be practiced otherwise than an specifically dis- 
withstand the constant flexing around wheels 12 and 14. 15 closed. 
It has been found that stainless steel wire will meet all of Accordingly, the invention having been described in 
these conditions. its best embodiment that which is desired to be claimed 
Wires 38 interconnect rods 30 by extending along the by Letters Patent is: 
top 40 of each of the rods and are looped around prese- 1. A belt for transmitting power from a cogged driv- 
lected ones of the rods as at 42 because if loops 42 are 20 ing member to a cogged driven member, comprising; 
looped around each rod 30, wire 38 between adjacent a plurality of inflexible teeth means spaced along the 
rods will be inherently curved due to the effects of direction of travel of said belt, said teeth means 
looping causing belt 10 to stretch longitudinally when having a longitudinal axis transverse to said direc- 
the curved portion of the wire straightens under load tion of belt travel; and 
which may cause teeth slippage. In addition, by looping 25 a plurality of substantially inextensible fast means 
the wire around preselected rods the number of loops spaced transversely to said direction of belt travel 
per individual wire is reduced and because each loop is and extending in said direction of belt travel adja- 
a potential point for cracking and fatigue, a lesser num- cent to said teeth means, each of said fast means 
ber of loops minimizes the chances of belt failure. It is being looped around selective teeth means, at least 
preferred that adjacent wires 38 be looped around dif- 3o one unlooped teeth means being interposed be- 
ferent ones of rods 30 as illustrated in FIGS. 2 and 3 tween adjacent looped teeth means, and each fast 
because should an individual wire 38 break it will only means being looped around teeth means different 
effect those rods the wire is looped around. Thus, the from adjacent fast means, whereby said belt is sub- 
majority of rods 30 within belt 10 will not be effected by stantially immune from longitudinal stretching, 
one wire breaking which will minimize the chances of tooth slippage, fatigue, cracking, and premature 
teeth slippage and possible belt failure. By forming 35 failure. 
loops 42 around preselected rods 30, the rods are fixedly 2. The belt of claim 1 wherein each of said teeth 
interconnected and prevented from moving along axis 
36 and from shifting position along the direction of belt 3. The belt of claim 2 where in each of said cylindri- 
travel. This construction insures non-slippage of rods 30 
which would tend to cause premature failure of belt 10. 40 4. The belt of claim 1 wherein said fast means is a 
As more clearly illustrated in FIG. 3, each wire 38 is 
looped around every third rod 30 with each adjacent 5. The belt of claims 4 wherein said metal wire is 
wire 38 being looped on the next succeeding rod. In 
tying rods 30 together by wires 38 it is preferred that 6. The belt of claim 1 wherein each of said fast means 
each adjacent wire 38 be an individual wire which ties 45 is looped around said selective teeth means in accor- 
together each third rod as the wire encircles the periph- dance with the relationships M=K(N+ 1) wherein M is 
ery of belt 10. It has been found that by looping wire 38 the number of said teeth means in said belt, N is the 
around every third rod 30 the stretching of the wire number of said teeth means between consecutive loops 
caused by the inherent wire curve between loops is and K is an integer. 
minimized while at the same time providing adequate 50 7. The belt of claim 1 wherein each of said fast means 
support for each rod. To ensure the correct spacing is looped around said selective teeth means in accor- 
between each consecutive loop 42 of each individual dance with the relationship M=K(N+ 1)+ 1 wherein M 
wire 38, each wire is looped around rods 30 in accor- is the number of said teeth means in said belt, N is the 
dance with the relationship M=K(N+ 1) where M number of said teeth means between consecutive loops, 
equals the number of rods making up belt 10, N is equal 55 and K is an integer. 
to the number of rods between consecutive loops, and 8. The belt of claim 1 wherein each of said fast means 
K is any integer. For example, where N is equal to 2 and is looped around said selective teeth means in accor- 
K is equal to 6, M will be equal to 18. dance with the relationship M=K(N+ 1)- 1 wherein M 
Although the above configuration is preferred, other is the number of said teeth means in said belt, N is the 
arrangements may also be used. Instead of having a number of said teeth means between consecutive loops, 
plurality of individual wires 38 connecting rods 30, a 6o and K is an integer. 
single wire may be used by winding the single wire 9. The belt of claim 1 further including flexible means 
around a multiplicity of teeth around the periphery of encapsulating all of said teeth means and said fast 
belt 10 to form a plurality of adjacent wires 38. To means. 
ensure the correct spacing of each loop 42 when using 10. The belt of claim 9 wherein said flexible means is 
this configuration, the wire 38 is looped around rods 30 65 rubber. 
in accordance with the relationship M=I<(N+ 1)+ 1 or 11. The belt of claim 9 wherein said flexible means is 
M=K(N+ 1)- 1 where M, K, and N are the same as plastic. 
5 
means is a cylindrical metal rod. 
cal metal rods is stainless steel. 
plurality of spaced metal wires. 
stainless steel. 
I 
previously described. For example, in the relationship + e + + +  


Belt for transmitting power from a cogged driving member to a cogged driven member

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