A prosthetic device for below-the-elbow amputees is disclosed. The device has a removable effector, which is attached to the end of an arm cuff. The effector is comprised of a pair of C-shaped members that are oriented so as to face each other. Working in concert, the C-shaped members are able to hold a bar such as a chainsaw handle. A flat spring is fitted around the C-shaped members to hold them together

Belcher, Jewell G.

Carden, James R.

Norton, William E.

Vest, Thomas W.

English

NASA Technical Reports Server

111111 1ll1ll Ill 11111 11111 Il1 11111 11111 11111 Il1 Il11 1l111111 Il1 Il1 
United States Patent 1191 
US005163966A 
[ i i ]  Patent Number: 5,163,966 
Norton et al. [45] Date of Patent: Nov. 17, 1992 
[54] BAR-HOLDING PROSTHETIC LIMB 3,735,426 5/1973 Horvarh ................................ 623/65 
[75] Inventors: 
[73] Assignee: 
[21] Appl. NO.: 
[22] Filed: 
William E. Norton; Thomas W. Vest; 
Jewel1 G. Belcher, Jr.; James R. 
Carden, all of Huntsville, Ala. 
The United States of America as [571 ABSTRACT 
represented by the Administrator of 
the National A~~~~~~~~~~ and space 
Ahinkbation, Washington, D.C. 
873,931 
Am. 15. 1992 
Primary Examiner-Ronald Frinks 
Attorney, Agent, or Firm-Robert L. Broad, Jr.; Guy M. 
Miller; John R. Manning 
A prosthetic limb (10) for a below-the-elbow amputee is 
constructed having a removable effector (16) remov- 
ably mounted in a mount (18) having semicircular bands 
(20) set by “hand lapped” construction in sides of a 
body (12) near a closed end (22) thereof. The effector 
(16) is offset from the body (12) and is provided with 
supports (60, 62), each having a C-shaped slot (64, 66) 
for receiving a horizontally oriented bar, such as that on 
a chainsaw. A pair of semi-circular gripping members 
(68, 70) are pivotally mounted by pins (72, 74) near a 
closed end of the slots (64,66) and are biased closed by 
a C-shaped leaf spring (90) disposed about an outer 
periphery of the members (68, 
................................................ [51] Int. C1.5 A61F 2/54 
[52] US. CI. ......................................... 623/65; 623/57 
[58] Field of Search ........................ 623/65, 57, 61, 62 
[561 References Cited 
U.S. PATENT DOCUMENTS 
1,213,222 1/1917 McKay ............................. 623/65 X 
1,711,447 4/1929 Colanduoni ...................... 623/65 X 
2,427,974 9/1947 Otterman .............................. 623/62 
2,561,523 7/1951 Lux ................................... 623/65X 14 Claims, 3 Drawing Sheets 
https://ntrs.nasa.gov/search.jsp?R=19930005681 2020-03-24T07:24:01+00:00Z
U.S. Patent Nov. 17, 1992 Sheet 1 of 3 5,163,966 
U.S. Patent Nov. 17, 1992 Sheet 2 of 3 5,163,966 
US. Patent Nov. 17, 1992 Sheet 3 of 3 5,163,966 
5.163,966 
1 
BAR-HOLDING PROSTHETIC LIMB 
ORIGIN OF THE INVENTION 
The invention described herein was made in the per- 
formance of work under a NASA contract and is sub- 
ject to the provisions of Section 305 of the National 
Aeronautics and Space Act of 1958, Public Law 85-568 
(72 Stat. 435; 42 US. C. 2457). 
FIELD O F  THE INVENTION 
This invention relates generally to prosthetic limbs 
for below-the-elbow amputees, and more particularly to 
such a limb adapted for lifting bars or tubular members 
such as the bar on a chainsaw. 
BACKGROUND OF THE INVENTION 
In the past, below-the-elbow amputees have had very 
few realistic choices available to them for assisting them 
in performing heavy duty tasks. Although so-called 
“bionic” prosthetics are available, drawbacks of these 
devices are numerous and include cost of the limb, 
which can easily run into the tens of thousands of dol- 
lars, cost of batteries, weight of the device, its durabil- 
ity, and the necessity to keep it internally clean and dry. 
As a result, these “bionic” devices have not been widely 
accepted by amputees, and prosthetic devices which 
utilize body motions to perform selected tasks are gen- 
erally preferred. However, the pulleys, traction de- 
vices, and complexities of these type devices also have 
limitations with respect to cost, comfort, and durability. 
As a result, prosthetics tailored to a specific purpose 
appear to be best suited for an active amputee. 
Of the prosthetic device of this last class, perhaps the 
closest to applicants’ device is U.S. Pat. No. 1,711,447, 
issued on Apr. 30, 1929, to Colanduoni, which discloses 
a forearm prosthetic device having an axially inserted 
member with opposed leaf springs adapted to grip a ball 
mounted on a steering wheel of a vehicle or to a gear 
shifting rod. No provision is made in this prosthetic 
device to grip a tubular object. Another below-the- 
elbow device is disclosed in U.S. Pat. No. 1,213,222, 
issued on Jan. 23, 1917, to McKay, which discloses a 
prosthetic mount having an axial, splined mounting 
recess provided with a catch and a plurality of fittings, 
each with a specific purpose and each having a like, 
splined mount for mounting in the recess. One of the 
fittings disclosed in this patent (FIGS. 6 and 7) shows a 
spring-loaded clamp-like fitting disposed for holding a 
handle such as that found on a rake or shovel. However, 
the angle of the splined mount makes this fitting unsuit- 
able for holding a chainsaw bar or other horizontal 
tubular member, Additionally, this fitting does not ap- 
pear to possess the durability or structural rigidity nec- 
essary to perform heavy lifting. 
In accordance with the foregoing, it is the object of 
this invention to provide a prosthetic device for a be- 
low-the-elbow amputee which is adapted to allow the 
amputee to easily work with horizontal tubular mem- 
bers such as the bar found on a chainsaw. 
SUMMARY OF THE INVENTION 
This invention is a prosthetic limb for a below-the- 
elbow amputee that will allow the amputee to lift or 
otherwise manipulate horizontal bars or tubes such as 
the bar on a chainsaw. The limb is constructed having a 
hollow body adapted to receive a stump of the forearm 
of the amputee and is provided with a mount having a 
receptacle offset from the body. An effector is mounted 
in the receptacle, the effector having a C-shaped slot 
facing forward of the body and constructed to support 
a load associated with the bar. A C-shaped gripping 
5 member for gripping the bar is pivotally disposed in the 
effector to partially close the slot and is provided with 
biasing means to bias the gripping member closed. 
BRIEF DESCRIPTION OF THE DRAWINGS 
FIG. 1 is a perspective view partially out away of a 
FIG. 2 is a planar view from the effector end of the 
FIG. 3 is a planar view of the effector as seen from 
10 
prosthetic limb of the present invention. 
invention, also partially cut away. 
l5 one side. 
DETAILED DESCRIPTION OF THE 
DRAWINGS 
Referring initially to FIG. 1, a prosthetic device 10 is 
2o shown for a below-the-elbow amputee, the device being 
adapted to allow the amputee to easily work with hori- 
zontal tubular objects such as the bar on a chainsaw, the 
handle of a push cart, dumb bells involved with weight 
lifting, etc., this bar being illustrated in FIG. 1 by 
25 dashed lines 15. In this device, a cast-like, hollow body 
12 is constructed to fit over the stump of the wearer’s 
forearm and is conventionally held in place with straps 
(not shown) particular to those found in the art. Body 
3o 12 is also constructed to allow lifting of heavy objects 
and yet be as lightweight as possible. One example of 
such construction is found in the manufacture of higher- 
quality recreational boat hulls wherein fiberglass net- 
ting impregnated with uncured, liquid resin mixed with 
35 hardener is placed on a core to form the hull. This 
“hand-lapped” construction in a prosthetic limb, yields 
a strong, durable, lightweight device with a fitting, or 
effector assembly 14, that will not become loose due to 
vibration or heavy use. 
Effector assembly 14, as shown in the drawings, is 
constructed of two parts, a detachable effector 16 and a 
mount 18. Mount 18 is provided with anchor bands 20 
of a semi-circular or circular shape, with bands 20 em- 
bedded in body 12 and wrapped with fiberglass netting 
45 19 utilizing the “hand-lapped” construction described 
above. Bands 20 are positioned adjacent to each 22 of 
body 12 and are set in body 12 to partially or wholly 
encircle sides of body 12 (dotted lines) such that mount 
18 is offset from an axis 24 longitudinally extending 
50 through body 12. Thus, with plastic-coated fiberglass 
webbing wrapped around anchor band 20 and set in 
body 12 as described, a tough, durable anchoring is 
provided for mount 18. On the other side of mount 18 is 
a receptacle 24 having opposed, downwardly-extend- 
55 ing, elongated receiving lugs 26 and 28 (FIGS. 1 and 2). 
Lugs 26 and 28 each are constructed with inner facing 
walls 30 and 32 (FIG. 2), respectively, with opposed 
grooves 34 and 36 cut in facing walls 30 and 32. Bolts 38 
serve to lock effector 16 in place and are threaded into 
60 threaded openings 44 (only one shown in FIG. 3) in 
lower sides of lugs 26 and 28, with openings 44 commu- 
nicating as shown with grooves 34 and 36. 
For removably mounting effector 16 in mount 18 and 
referring to FIG. 2, a quick disconnect means having 
65 opposed upper edges 46 and 48 of effector 16 are each 
provided with elongated, outwardly-extending opposed 
rails or flanges 50 and 52 which slidably engage grooves 
34 and 36 of lugs 26 and 28. Bolts 38, when tightened, 
4o 
5.163.966 
3 
bear on bottoms 54 and 56 of rails or flanges 50 and 52, 
clamping effector 16 in place in receptacle 24. 
Effector 16 is further configured with spaced down- 
wardly-extending supports or support arms 60 and 62, 
which are formed on and extend from upper edges of 
band 48, respectively. Supports 60 and 62 are provided 
with aligned C-shaped slots 64 and 66 positioned in 
supports 60 and 62 such that the open region of slots 64 
and 66 faces forward of body 12. Supports 60 and 62 
serve to receive weight or other forces applied to effec- 
tor 16 when a horizontal, tubular member is held in slots 
64 and 66. 
For generally providing gripped engagement with a 
tubular handle or object positioned in slots 64 and 66, a 
pair of opposed, upper and lower half C-shaped clamp- 
ing or gripping members 68 and 70 are pivotally 
mounted as shown between supports 60 and 62. Grip- 
ping members 68 and 70 pivot around pins 72 and 74 
located as shown near the closed ends of slots 64 and 66, 
which pins extend through supports 60 and 62 and the 
respective gripping member. Additionally, gripping 
members 68 and 70 extend circularly past edges 76 and 
78 (FIG. 3) of slots 64 and 66 in supports 60 and 62. 
Alternatively, one or the other of gripping members 68 
and 70 may be fixed in place or be integral with supports 
60 and 62, with the other gripping member disposed in 
pivoting relation between supports 60 and 62. Ends 80 
and 82 of gripping members 68 and 70 define a gap 84 
through which a tubular object is forced into slots 64 
and 66. 
For providing gripped engagement with a bar or 
tube, the outer periphery of gripping members 68 and 
70 are provided with a groove or recess 88 (FIGS. 2 and 
3) within which a C-shaped spring 90 is fitted. Spring 90 
serves to bias gripping members 68 and 70 together in 
closed relation with respect to gap 84, loosely holding 
or gripping a bar in slots 64 and 66. If desired, frictional 
or protective pads (not shown) may be placed along 
inner surfaces of slots 64 and 66 and gripping members 
68 and 70 to effect a frictional engagement of a bar or 
when it is desired not to mar surfaces of the bar. Addi- 
tionally, the degree of gripping forces exerted by the 
gripping members may be adjusted by adding additional 
springs or changing the spring in gripping members 68 
and 70 to a stiffer or less stiff spring. 
In use, the wearer of the prosthetic device forces a 
bar or tubular handle, such as the bar on a chainsaw, 
into gap 84, forcing gripping members 68 and 70 to 
pivot slightly against spring 90 and admit the bar into 
slots 64 and 66 of supports 60 and 62. The bar may then 
be lifted or pushed by the user, with weight associated 
with the bar, such as a chainsaw, bearing on or against 
supports 60 and 62. To release the bar, the user forces 
the bar outward through gap 84 defined by gripping 
members 68 and 70. 
Having thus described our invention and the manner 
of its use, it is apparent that, incidental modifications 
may be made thereto which fairly fall within the scope 
of the following appended claims, wherein we claim: 
1. A prosthetic device for a below-the-elbow ampu- 
tee that will allow the amputee to lift and manipulate 
horizontally disposed bars and tubes, comprising; 
a generally hollow body having an open end disposed 
to receive a stump of a forearm of the amputee; 
a mounting assembly anchored in an opposite end of 
said body and having a receptacle on one side, said 
receptacle being offset from an axis extending 
through said body; and 
4 
an effector disposed for removable mounting in said 
receptacle, said effector comprising; 
a pair of support means each defining a C-shaped 
slot, with an open region of said slot facing for- 
ward of said body in a plane along said axis for 
receiving lifting or pushing forces applied to said 
bar, 
gripping means including at least one semicircular 
gripping member positioned between said pair of 
support means and partially encircling the open 
region of said slot at one end, defining a gap 
therein, and disposed for pivotal movement at an 
opposite end near a closed end of said slot for 
holding said bar in said slot, and 
biasing means coupled to said gripping member for 
biasing said gripping member toward said slot, 
for holding said bar within said slot, whereby as 
said bar is forced into said gap, said gripping 
member being urged away from said slot, allow- 
ing passage of said bar into or out of said slot. 
2. A prosthetic limb as set forth in claim 1 wherein 
one end of said mounting assembly is provided with 
opposed semi-circular bands rigidly set by hand lapped 
construction in sides proximate said opposite end of said 
3. A prosthetic limb a set forth in claim 1 wherein said 
effector comprises a pair of opposed, outwardly-extend- 
ing rails on said effector, and said mounting assembly is 
provided with opposed, downwardly-extending lugs 
30 having inner facing walls, with an aligned groove in 
each of said facing walls, for receiving said rails, and 
locking bolts threadably engaging threaded openings in 
lower sides of said lugs, said openings in communicating 
relation with said grooves, clamping against said rails 
4. A prosthetic limb as set forth in claim 1 wherein 
said biasing means comprises a semi-circular left sprhg 
disposed in a peripheral groove in said gripping member 
for biasing said gripping member toward said slot. 
5. A prosthetic limb as set forth in claim 1 wherein 
said gripping means comprises a pair of opposed, semi- 
circular gripping members pivotally mounted between 
said support members, each pivotally mounted at one 
end near said closed end of said slot. 
6. A prosthetic limb for a below-the-elbow amputee 
which will allow the amputee to lift and manipulate 
horizontally disposed bars and tubes comprising; 
a generally hollow body having one end disposed to 
fit over the stump of a forearm of the wearer; 
a mount anchored in an opposite end of said body, 
said mount having a receptacle offset from an axle 
extending through said body; and 
an effector disposed for removable mounting in said 
receptacle, said effector comprising: 
support means for applying lifting and pushing 
forces to a bar, said support means having a 
C-shaped slot for receiving said bar, with an 
open region of said slot facing forward of said 
M Y ?  
at least one semi-circular gripping member having 
one end disposed for partially encircling an open 
end of said slot and defining a gap therein and 
pivotally mounted at an opposite end near a 
closed end of said slot, for holding a bar in said 
biasing means connected to said gripping member 
for biasing said gripping member toward said 
slot and against said bar. 
5 
10 
15 
20 
25 body. 
35 and holding said effector in place. 
40 
45 
50 
55 
60 
65 slot, and 
- -5,163,966 
5 
7. A prosthetic limb as set forth in claim 6 wherein 
said mount comprises a circular band set in said oppo- 
site end of said body. 
8. A prosthetic mount as set forth in ciaim 7 wherein 
said effector comprises opposed, outwardly-extending 5 
rails, and said receptacle is provided with opposed lugs 
having facing surfaces, with opposed grooves in said 
facing surfaces for receiving said rails. 
9. A prosthetic limb as set forth in claim 8 wherein 
said gripping member comprises a pair of opposed, 10 
semi-circular gripping members pivotally mounted at 
one end near a closed end of said slot. 
10. A prosthetic limb as set forth in claim 9 wherein 
said biasing means comprises a C-shaped leaf spring 
fitted around an outer periphery of said gripping mem- 15 
bers. 
11. A prosthetic limb as set forth in claim 10 compris- 
ing a locking bolt threadably engaging a threaded open- 
ing in at least one of said lugs, said opening communi- 
cating with one of said grooves, for bearing against one 20 
of said rails and locking said effector in said lugs. 
12. A prosthetic device for a below-the-elbow ampu- 
tee that will allow the amputee to lift and manipulate 
bar-like members, comprising: 
25 
6 
a cuff having a closed end and an open end disposed 
for receiving the stump of a forearm of the ampu- 
tee; 
a support member carried adjacent to said closed end 
of said cuff and provided with opposed spaced 
faces, each having a groove therein; 
an effector assembly including gripping means for 
peripherally engaging said bar-like member for 
gripped engagement therewith; and 
quick disconnect means secured to said effector as- 
sembly comprising a pair of opposed flanges, each 
disposed for slidable relation in a said groove, and 
means for securing each said flange in each said 
groove. 
13. A prosthetic device as set forth in claim 12 
wherein said gripping means includes a pair of opposed 
clamping members and biasing means for biasing said 
clamping members into and out of said gripped engage- 
ment. 
14. A prosthetic device as set forth in claim 13 inciud- 
ing a pair of spaced support arms for support of said 
gripping means thereon, each said support arm depend- 
ing from a said flange of said quick disconnect means. * * * * *  
30 
35 
40 
45 
50 
55 
65 


Bar-holding prosthetic limb

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