Crab peeler

Crab meat is removed from cooked crabs by placing the cooked crabs on a platform and then subjecting them to an increasing, almost vertical, pressure by passing a convex surface over them. The meat is thereby expressed from the peel and falls into a receptacle. The peel adheres to the convex surface to be scraped off and away by a scraping blade.

My invention relates to apparatus and method for removing meat from crabs, 
and may be useful for similar products. 
Crab meat is an important food. Removing the crab meat from the crab 
presents great difficulties, however. Peeling crab by hand is a slow and 
expensive process. A mechanical crab peeler has long been sought, but 
efforts have resulted in devices which were either too expensive or did 
not perform properly. Many of these machines tend to mash the meat, 
producing a mushy and fine end product. 
It is an object of my invention to provide a mechanical device which can 
efficiently peel crabs, and which will produce crab meat which is whole 
and firm. This object is accomplished in my invention by passing a convex 
surface, such as a semicylindrical roller, over the crabs as they lay on a 
platform to create a nearly vertical increasing pressure on the crabs to 
express crab meat from the peel.

DETAILED DESCRIPTION 
In the present invention, crab meat is removed from previously cooked crabs 
by placing the cooked crabs on a platform and then using a convex surface 
to apply an increasing, almost vertical, pressure to the crabs to express 
the crab meat from the peel. The expressed meat falls into a meat 
receptacle at one end of the platform; the peels adhere to the convex 
surface and are scraped therefrom and off the other end of the platform by 
a blade. 
The drawings illustrate a preferred embodiment of the present invention. 
Referring now to FIGS. 1-6, it can be seen that the platform 1 has a top 
surface 2 and a bottom surface 3. A convex surface is provided by roller 4 
which is disposed so as to be able to roll along the top surface 2 of 
platform 1. In the preferred embodiment, the convex surface is a section 
of a cylindrical surface, and subtends an arc angle of about 180.degree.. 
The convex surface may, however, define an entire cylindrical surface or 
any other surface not inconsistent with the application of pressure to the 
top surface 2 by rolling action. Thus, a full cylindrical roller could be 
used in my invention. Roller 4 is made of metal but other materials may 
also be suitable. 
It is desirable that the angle of contact between the platform 1 and the 
roller 4 be small in order to allow the roller 4 to apply an almost 
vertical pressure on the crabs which gradually increases as the roller 4 
advances over them. It is clear that the angle of contact between the 
platform 1 and roller 4 varies inversely with the radius of roller 4 so 
that a large radius will produce a small angle of contact. In the 
preferred embodiment, a radius of 5 inches has been found satisfactory, 
but it is clear that other radii may be chosen. 
In the preferred embodiment, the roller 4 is supported through its center 
by an axle 5 resting in bearings 6. The bearings 6 are mounted on a drive 
frame 7 which is mounted to reciprocate in a plane parallel to, but above, 
the plane defined by the platform 1. Drive frame 7 includes a tongue 
member 31, cross bar member 32 and fork members 33 and 34. Rigidly 
depending from fork members 33 and 34 are arm members 35 and 36. Pressure 
rollers 37 and 38 are mounted on arm members 35 and 36 so as to be able to 
roll along guide rails 30 affixed to each side of platform 1; they serve 
to restrain any upward movement of roller 4. 
By its reciprocation, drive frame 7 drives the roller 4 through its 
bearings 6 back and forth along the top surface 2 of platform 1. 
Reciprocating thrust for the drive frame 7 is provided by drive means 
through a yoke 8. In the preferred embodiment, the drive means comprises 
an electric motor 9, the rotating shaft of which imparts its rotary motion 
to crank 10 through gear box 11 by which the rpm of crank 10 may be 
adjusted. Crank 10 is connected to a connecting rod 12 for converting the 
rotary motion of crank 10 to back and forth reciprocating motion in the 
manner well known to those of ordinary skill in the mechanical arts. It 
will be clearly understood, however, that any means which can impart 
reciprocal back and forth motion would be suitable as drive means for my 
invention. For example, the electric motor 9 and gear box 11 could be 
replaced by manually operated means to impart rotary motion to crank 10. 
As another example, a gasoline engine may be substituted for electric 
motor 9. 
The reciprocating back and forth movement of connecting rod 12 is 
transmitted to drive frame 7 (and thus to roller 4) by yoke 8. Yoke 8 is 
comprised of a frame having sides 13 and 14 and crosspiece 15. In 
crosspiece 15 is a hole threaded to receive threaded bolt 16, the end of 
which contacts tongue 31 of drive frame 7. By adjusting bolt 16, the 
pressure of roller 4 on the top surface 2 of platform 1 may be adjusted. 
Yoke 8 is connecting to drive frame 7 by pin 17 which passes through 
receiving holes in sides 13 and 14. Yoke 8 is connected to connecting rod 
12 by another pin 18 which passes through horizontal slots 19 and 20 in 
sides 13 and 14. The length of slots 19 and 20 is substantially greater 
than the diameter of pin 18. It is pin 18 which actually transmits the 
reciprocating back and forth movement of connecting rod 12 to yoke 8. 
However, such movement is only transmitted when pin 18 engages sides 13 
and 14 of yoke 8 at the ends of slots 19 and 20. During the time that pin 
18 travels back and forth between the ends of slots 19 and 20, it is not 
engaged with sides 13 and 14 and none of the reciprocating back and forth 
motion of connecting rod 12 is then transmitted to yoke 8. Pin 18 is then 
said to be exhibiting lost motion, since its motion is lost as regards its 
ability to transmit its motion to yoke 8. 
In the preferred embodiment, a guide wheel 21 is located between sides 13 
and 14 and pins 17 and 18. The guide wheel 21 is connected through its 
axis of rotation to yoke 8 by pin 22 which passes through receiving holes 
in sides 13 and 14. The diameter of guide wheel 21 exceeds the width of 
sides 13 and 14, thus permitting it to engage guide rail 23. Guide rail 23 
is fixed with respect to roller 4, but is aligned in the direction of its 
advance. The back and forth movement of the guide wheel 21 along guide 
rail 23 in response to the reciprocating back and forth movement of yoke 8 
is synchronous with the movement of roller 4 and ensures the precision and 
accuracy of its back and forth movement. 
To ensure roller 4 from slipping during its back and forth movement (i.e., 
to ensure that its back and forth movement is achieved by rolling and not 
sliding), there is rigidly fixed to the axle 5 of roller 4, a pinion gear 
24 which engages a rack 25 which is fixed relative thereto. While the 
pinion gear 24 of the preferred embodiment is a sectional pinion gear, 
similar in size and shape to the cross-section of roller 4, it is clear 
that pinion gears of different size and shape may be employed, just as a 
full cylindrical roller may be used instead of sectional cylindrical 
roller 4 of the preferred embodiment. Further, while the rack 25 of the 
preferred embodiment is of the bicycle chain type, it is clear that other 
rack types would be suitable. 
A feature of the claimed invention is a scraping blade 26 which is 
connected to yoke 8 by means of a bell crank 27 and a turnbuckle 28. The 
bell crank 27 is attached through its center to drive frame 7 by a pin 29 
and is free to pivot thereabout. To one arm of bell crank 27 is attached 
one end of turnbuckle 28. The other end of turnbuckle 28 is attached to 
one end of pin 18. Thus, the turnbuckle 28 partakes of the lost motion 
movement of pin 18, and when it does so, it causes the bell crank 27 to 
pivot about pin 29, since pin 29 is attached to drive frame 7 and does not 
partake of the lost motion movement of pin 18. The turnbuckle 28 and 
scraping blade 26 are attached to the arms of bell crank 27, the 
particular arms being so chosen so that when the lost motion movement of 
pin 18 is in the direction of roller 4, the scraping blade 26 is pivoted 
upward to ensure contact with the rolling surface of roller 4. This 
position of scraping blade 26 relative to roller 4 is maintained as roller 
4 advances along the top surface 2 of platform 1. (Roller 4 is said to be 
advancing when it is being pushed by drive frame 7). When the lost motion 
movement of pin 18 is in the direction away from roller 4, the scraping 
blade 26 is pivoted downward to ensure scraping contact with the top 
surface 2 of platform 1. This position of scraping blade 26 relative to 
the top surfacd 2 of platform 1 is maintained as the roller 4 retreats 
along the top surface 2 of platform 1. (Roller 4 is said to be retreating 
when it is being pulled by drive frame 7). Scraping blade 26 thus moves 
ahead of roller 4 during the retreat of roller 4, scraping the top surface 
2 of platform 1 as it so moves. 
The operation of the machine may be understood by referring to FIGS. 7 and 
8. In FIG. 7, clean halves of par-boiled crabs (outer shell and intestines 
removed) have been placed on the top surface 2 of platform 1 along the 
path on which the roler 4 will advance when pushed by drive frame 7. As 
roller 4 is pushed by drive frame 7, it rolls forward to apply an 
increasing and almost vertical pressure to the cooked crabs as it passes 
over them which results in the meat being squeezed or expressed from the 
crab peels. The meat falls into a receptacle 39 at the end of platform 1. 
The crab peels adhere to the surface of roller 4 and are scraped onto the 
top surface 2 of platform 1 by scraping blade 26. Scraping blade 26, was 
of course, in scraping position with respect to roller 4 before it began 
its advance, due to the lost motion movement described above. Having 
expressed the crab meat in FIG. 8, the roller 4 retreats, as illustrated 
in FIG. 8. In FIG. 8, roller 4 is pulled back by drive frame 7, the lost 
motion movement having already placed scraping blade 26 in scraping 
position with respect to the top surface of platform 1. Scraping blade 26 
then moves ahead of roller 4, scraping the peels off the end of platform 
opposite the end associated with the meat receptacle 39. Once cycle of 
operation is thus complete and the machine is now ready to receive more 
cooked crabs to begin another cycle. 
As mentioned earlier, the pressure of roller 4 on the top surface 2 of 
platform 1 may be adjusted by adjusting threaded bolt 16. If the bolt 16 
is turned so as to raise crosspiece 15 relative to the tongue 31, the yoke 
8 (or to be more precise, the sides 13,14 of yoke 8) will pivot in an 
anti-clockwise direction about axle 22, as can be visualized in FIG. 2, 
thereby tending to lower pin 18 and raise pin 17. This movement causes 
tongue 31 to be lifted in a clockwise direction about pressure rollers 37 
and 38, thus lowering roller 4, and increasing the pressure of roller 4 
against the top surface 2 of platform 1. 
Although the invention has been described in detail for the purpose of 
illustration, it is to be understood that such detail is solely for that 
purpose and that variations can be made therein by those skilled in the 
art without departing from the spirit and scope of the invention except as 
it may be limited by the claims.