Ratchet mechanism for high speed operation at reduced backlas

Dane, D. H.

English

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REPLY TO 
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TO: 
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION 
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61/sc ient i f  i =  6i Technical Intomarron Diviaion 
Attention: Miss Winnie M. Morgan 
FROM: G P / O ~  f ice of A s s i g  t ap t  General .Counsel fo r  
Patent Matters 
SUBJECT: Announcement of NASA-Owned U. 8. Patents i n  STAR 
In accordance with the procedures agreed upon by Code GP 
and Code USI, the attached NASA-owned U, 8. Patent is being 
forwarded for  abstracting and announcement i n  NASA STAR, 
U. S. Patent No. 
Government or  
Corporate Employee 
Supplementary Corporate 
Source ( i f  applicable) r 
' MFs - NASA Patent Case No. : 
NOTE - If  t h i s  patent covers an invention made by a corporate 
employee of a NASA Contractor, the following is applicable : 
yes NO 
Pursuant t o  Section 305(a) of the National Aeronautics and 
Space Act, the name of the Administrator of NASA appears on 
the first page of the patent; however, the name of the actual 
inventor (author) appears a t  the heading of Column No. 1 of 
the Specification, following the word8 a. . , w i t h  respect t o  
Enclosure 
Copy of Patent a i t ed  abwe 
https://ntrs.nasa.gov/search.jsp?R=19710008330 2020-03-17T02:46:34+00:00Z
Patented Oct, 20, 1970 3,534,836 
Sheet of  2 
F I G .  
IN VEM TOR 
ATTORNEYS 
Patented Oct, 20, 1990 
Sheet 2 01' 2 
FIG. 2 
i N  VEM TOR 
DAN H. DANE 
6 
ATTORNEYS 
[/2] liavenrtor Dan H. Ewe 
W~nts.;il!e; l akm2 
(2 I 1 Appl. No. 458,082 
[22] Filed Sp t .  6,1968 
145 1 Patented W, 20, 1 WU 
1'75 j Assignee The United States of America as represented 
by the AddnisPrator &the National 
Aeronautits and Space Administrdon 
[54] RATCHm MECHANISM 
5 Claims, 4 Drawing Figs. 
[52] U.S. CI ....................................................... 192143.1, 
8 1163.1 
[Sl ]  Int.CI ........................................................ F l 1 3 1 0 6 ,  
F16d23112 
[50] Field of Search. ........................................... 19214 1.3, 
43.43.1; 81163.1 
[561 References Cited 
UNITED STATES PATENTS 
..................... 1,569,5 16 111926 Mangham 192143 
2,028,876 1/19336 korts ............................ 192/41.3UX 
.......................... 2,113,722 4 i i938 Dodge 192143 
3,086,405 411 963 Fleming .................... .... 192143. IUX 
3,21c1,544 1 111965 Ryan ........................... 393/41.3UX 
Piiriiar)~ E:rairliner-Allaii D. Pierrrnarlll 
.4ttortze~~s-L. D. Wofford, Jr., C. C .  Wells and 0. T. McCay 
ABSTRACT: A ratcheting mechanism comprising a housing, a 
socket member rotatably mounted therein and a number of 
paired sprag members pivotally mounted in spaced notches on 
the socket member. A control member mounted in the hous- 
ing is rotated in either direction to engage and pivot a desired 
one of each sprag pair away from the housing. The other sprag 
of each pair will permit rotation of the housing relative to the 
socket member in the direction of the pivoted sprag, but will 
jam if the housing is rotated in the other direction, thereby 
providing a ratcheting action between the housing and socket. 
A knob attached to one end of the control member for rotat- 
ing the control member against the sprags is secured through a 
friction lock to a knob bolted to a shaft that is keyed to the 
socket member. 
3,534,836 
1 2 
RATCHET MECHANISM sptag members 24 are mounted in pairs in these nolrhes. The 
sprags are held in an upstanding or radially extending position 
The invention described herein was made by an employee by a coil spring 26 mounted through and attached to each 
of the U.S. Government and may be manufactured and used sprag. The sprags, for reasons discussed hereafter, are of suclz 
by or for the Government of the United States of America for. 5 length that they will engage the housing unless pivoted out of 
governmental purposes without the payment of any royalties contact with the housing. 
thereon or therefor. A control member 28 is mounted in housing 12 and suo- 
BACKGROUND OF THE INVENTION 
The invention relates to ratchet mechanisms and more par- 
ticularly it relates to an improved ratchet mechanism capable 
of very high speed operation with reduced backlash as com- 
pared to presently available ratchet devices. 
Ratchet mechanisms available heretofore have generally in- 
cluded a spring and pawl arrangement where the spring biased 
pawl engages the teeth of a driven gear. The pawl is arranged 
so as to be cammed away from the gear teeth upon rotation of 
the gear in one direction, but forced into engagement with the 
gear teeth to perform a wedging action that immobilizes the 
gear when the gear is turned in the other direction. 
While effective this type of ratchet necessarily includes con- 
siderable drag or friction between moving parts like the pawl 
and gear, particularly when the ratchet is designed to accom- 
modate high loading. Also, a fairly considerable amount of 
backward or opposite rotation of the driven gear may occur 
before the pawl wedges into the gear teeth to immobilize the 
gear. While this backward rotation will normally amount to 
only a few degrees, even this much backlash is objectionable 
in many applications. Also, spring and pawl ratchets are 
noisey at high speed and the pawl will be thrown away from 
the gear far enough that considerable backward rotation of 
the gear can occur, perhaps half a turn, before the pawl spring 
can return the pawl to immobilize the gear against backward 
motion. 
SUMMARY OFTHE INVENTION 
" 
ported for rotation therein by ball bearing 30 which rides 
against a bearing surface 32 in end cap 34. End cap 34 is 
l o  secured in place by snap ring 35. The control member in- 
cludes projecting lug members 36 that extend into the space 
between the sprags of each sprag pair so as to engage a 
selected one of the sprags of each sprag pair when the control 
member if rotated relative to the socket member. Both the 
l 5  socket member and control member are mounted on a shaft 
38 whose longitudinal axis coincides with that of housing 12, 
the control member, and the socket member. It will be noted 
from FIG. 2 that shaft 38 has a large end 40 keyed to the 
20 socket member by key 42 and a smaller end 44. The control 
member is mounted on end 44 of shaft 38 with a slip fit so as to 
be rotatable on the shaft. A knob 46 is bolted to end 44 of the 
shaft and a larger knob 48 is threaded into one end of the con- 
trol member. Knob 48 and the control member rotate 
25 together. A friction or sprlng washer 49 is positioned around 
shaft 38 between knobs $6 and 48 to form a friction lock that 
permits relative rotation between the knobs, and thus relative 
rotation between the control member and socket member, 
only when considerable force IS exerted on knob 48 and knob 
30 46 is held stationary. Otherwise. when the mechanism is in use 
for example, such relative rotation does not occur. 
Referring now to FIGS 3 and 4, the operation of the sprags 
and control member to control the ratcheting action of the 
mechanism will be described. In this description if will be as- 
35 sumed that a socket tvve tool 50. see FIG. 1. is mounted on 
. . 
the large end of shaft 38 for rotation therewhh to tighten or 
loosen a bolt. The action of only dne sprag pair and lug 
- - -  
~h~ present invention provides a ratchet mechanism that is member will be described, but =-is obvious the description 
smoother, operates quietly and has no backlash in its 3600 will apply to each sPrag pair and associated lug member. 
rotation. The mechanism can also perform at high r,p,m,s 40 when lug member 36 is rotated relative to the socket 
without undesirable side effects like noise and increased member to engage sprag 24 at projection 52, as illustrated in 
backlash that accompany highspeed operation of spring and FIG. 3, the sPrag will be pivoted away from and out of contact 
pawl type ratchets. with inner surface 54 of the outer housing. In this position 
 hi^ is accomplishe~ by altering a sprag type reverse sprag 24 will not contact surface 54 of the housing to interfere 
locking clutch to make it function as a ratchet mechanism, A 45 with rotation of the housing in the direction of arrow A. Sprag 
socket member to which a tool is attached is mounted for rota- 24' is pivoted in a clockwise direction by any movement of the 
tion in an outer housing, ~h~ socket member has a plurality of housing in the direction of the arrow. Movement of the hous- 
notches formed in the periphery thereof in which a plurality of ing with respect to the socket member and SPrags in an OP- 
sprags are mounted in pairs. The sprags function to immobil- po~i te  direction to arrow A will result in sprag 24' being 
ize the socket member with respect to the housing when the pivoted in a counterclockwise direction until it wedges 
relative rotation is in one direction, but permit relative rota- between the socket member and the outer housing. ~ o t c h  22' 
tion in the other direction, thereby providing a ratcheting ac- in the socket member is shaped so as to permit sprag 24' to 
tion between the housing and socket member. A control pivot and similarly notch 22 will permit sprag 24 to ~ i v o t .  
member is also mounted in the housing and it functions to en- 55 Thus. when the control member is rotated to the ~osit ion 
gage the sprags in a manner such that the direction ofrelative shown in FIG. 3 there can be relative rotation between the 
rotation permitted can be selected. An adjustment mechanism and member (and therefore between 
that includes a friction lock is included for rotating and hold- 14 and socket 50 attached to shaft 38) only in the direction of 
ing the control member in a desired position. arrow A. When handle 64 is moved so as to rotate the outer 
60 housing in an opposite direction to arrow A the housing and 
BRIEF DESCRIQTlON OF THE DRAWINGS socket member wi!l be immobiiized with respect to one 
another and socket 50 wrll be turned when handle 14 1s 
FIG I rs a plctortal view of the ratchetlng mechanism, turned Actually, the position shown an FIG 3 would be used 
'IG Is a cross-secr'ona' 'Iew of Ihe mechanism a'ov'g lrne for tiightenrng a bolt or nut and if l t  were desrred to loosen a 
Z2ofFIG 1, 65 bolt or nut the control member would be roiatcd %a a positlon 
'IGS ' 're sk'ierndt3t ri'usrraricrns of 'prag and wherern the lug rnember would engage the sprags as illustrated 
Ire1 member aperatlorr InFlG 4 
Operation in the FIG. 4 position will not be described in DESCR'PT'oNoE:TME PREFERRED detail because of the similarity to the mode of operation 
Ratchet mechanism 10 shown in FIG. 1 includes an outer 70 shown and descdbed in FIG. Suffice it to say that in the 
housing 12 to which a handle 14 is attached. A socket member FIG. 4 position motion of the outer housing reiative to the 
16 is mounted for rotation in housing 12 by means of a ball socket member is permitted when the housing is moved in the 
bearing I8 which rides against surface 20 in housing 12 that direction of arrow B. The socket member and ?lousing are 
serves as a race. The socket member has a series of spaced locked together by movement of the housing in a direction op- 
notches 22 (FIG. 2) formed around the periphery thereof and 75 posite to that of arrow B. 
3,534,836 
3 4 
When the exterrding k g  members of the controi member relative to said socket member when suff\cierrt force is R X -  
are rotated relative to the sprag members so that none of the erted thereon. 
sprag members are contacted, the mechanism will not func- 3. The ratcheting rnecbanism recited in claim 2 wherein said 
tion as a ratchet. This is because relative rotation of the outer adjustment means further iitciudes: 
housing with respect to the socket member in either direction 5 a first knob mounted on the control mernber at the other 
results in one sprag of each sprag pair being wedged between end thereof opposite said projecting lugs for manually 
the socket member and outer housing so as to immobilize the rotating said control member and projecting lugs relative 
outer housing with respect to the socket mernber. to the socket member; 
l claim: a second knob mounted on an end of said shaft adjacent 
I. A ratcheting mechanism comprising: I I) said first knob for holding said socket member and sprags 
a cylindrical housing with a handle attached thereto for stationary while the control member is being rotated. 
rotating said housing; 4. The ratcheting mechanism recited in claim 3 wherein said 
a cylindrical socket member rotatably mounted in said friction locking means is a curved spring washer disposed 
housing and having a plurality of spaced notches formed between and contacted by said first and second knobs. 
in pairs around the periphery thereof; 15 5. In a mechanism of the type wherein a cylindrical housing 
a plurality of spaced and paired sprags pivotally mounted in has a cylindrical control member and a cylindrical socket 
the notches formed in said socket member, said sprags ex. member rotatably mounted therein and a series of spaced and 
tending outwardly toward the housing and held in a sub- paired sprags pivotally mounted in spaced notches on said 
stantially upright position by a circular coil spring passing socket member and extending radially outwardly to selectively 
through and fastened to each of ,he sprags. the length of 20 engage the inner surface of the housing to prevent relative 
the sprags being such that they engage the inner sur- rotation between the housing and socket member, the control 
face of said housing unless pivoted away from hous- member including projecting lugs on one end thereof posi- 
ing; tioned between the sprags of a sprag pair to selectively pivot 
a cylindrical member mounted for move- one ~ p r a g  of each sprag p a ~ r  away from the t~ousing to permit 
merit in said housing, said control member having a 25 rotdtion of the housing relative to the socket member only in 
rality of projecting lugs on one end thereof positioned the direction of the pivoted sprag member; an improvement 
between the sprags of each sprag pair, whereby the con- t h $ , " , " , " , " " , ~ ~ ~ ~ " , ~ ~ ~ ~ ~ ~ ~ ~ ~ , " t ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ , & ~ i d  socket 
trol member can be rotated to a position wherein the pro- member for position~ng the projecting Jugs of said control jecting lugswill each engage one sPrag of each sPr% pair 30 member relative to said socket member and sprag pairs to 
to pivot the engaged sprag away from the housing and select the sprag of each spray pair to be pivoted away 
thus permit rotation of the housing relative to the socket from sa~d  outer hous~ng and thereby control the direction 
member in the direction of the pivoted sprag member, in which there can he relatrve rotation between the outer 
and rotation of said housing in the other direction relative housing and the socket member, 
to said socket will be prevented due to a wedging action 35 handle means mounted on said housing for rotation thereof; 
between the housing and socket member of the sprag of said means connected to said control member and said 
each sprag pair not engaged by the control member, socket member Including 
whereby the socket member will rotate with the outer a shaft that is fixed to said socke; rnember and rotatable 
housing in only one direction and provide a ratcheting ac- in said control member. one end of said shaft being 
tion; 40 adapted to have a tool mounted thereon; 
a shaft mounted through said socket member and said con- a first knob fixed to said control member on the end 
trol member, said shaft being fixed to said socket and thereof opposite said projecting lugs, said first knob 
rotatable in said control member; and being mounted over said shaft; 
adjustment means connected to the shaft mounted through a second knob fastened to said shafl and positioned ad- 
said socket member and to said control member for rotat- 45 jacent said first knob; and 
ing the projecting lug members on said control member a friction locking means positioned between said first and 
relative to said socket member and sprags, thereby select- second knobs that immobilizes the control member 
ing the direction of rotation of the outer housing relative relative to said socket member in normal conditions of 
to the socket mem her. use. but permits relative rotation therebetween when 
2. The ratcheting mechanism recited in claim 1 wherein said 50 sufficient force is exerted on the control member and 
adjustment means further includes: the shaft is held stationary. 
a friction locking means that immobilizes the control 6 .  The mechanism recited in claim 5 where~n said friction 
member relative to said socket member in normal condi- locking is a washer. 
tions of use, but permits rotation of the control member 
55 


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