Automatic crab leg shell cutting-in machine

An automatic crab leg shell cutting-in machine for processing crabs' legs. In order to charge the cutting-in machine with crab legs at a predetermined processing rate, the upper and lower feed-belts are provided in the longitudinal direction of the machine. Rotary cutting-knives are arranged therebetween on the both sides of a cutting-in section and depressing plates serving to depress the upper and lower feed-belts are provided opposite each other in such a manner that the upper and lower feed-belts have an increased or decreased clearance therebetween in the cutting-in section depending upon the dimensional conditions of a crab leg to be processed. The depressing plates are held so as to be vertically displaced with the aid of resilient means or shock absorbing means, whereas the rotary cutting-knives are arranged so as to approach the longitudinal axis of the feed-belts or move away therefrom in cooperation with resilient means or shock absorbing means and bell cranks. Further guide-members having a U-shaped cross section are provided in front and behind the cutting-in section of the machine.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an automatic crab leg shell cutting-in 
machine in which a cutting-in operation is performed from the both sides 
thereof in the substantially horizontal direction. 
2. Description of the Prior Art 
Heretofore, the practice has been to cut in shoulder meat, cut off a part 
of the crab leg or cut in it by means of a kitchen knife and then push out 
the crab meat with the aid of a rod such as a chop-stick or the like. 
However, the conventional steps for cutting-in crab legs as described above 
have been accomplished only at a reduced operational efficiency. In face 
to improve the conventional steps of operations for achieving an increased 
efficiency, a variety of automatic cutting-in machines have been already 
proposed. Due to the fact conventional automatic cutting machines deeply 
cuts into the contents (leg meat) of the crab legs at the same time as 
cutting in their shells, it is a recognized drawback of conventional 
machines that the crab meat becomes damaged when is taken it out of the 
shell after completion of the cutting operation. The required crab meat is 
produced at a greatly reduced rate and the commercial value of the crab 
meat obtained is reduced due to the miserable appearance of the product 
obtained. 
OBJECT OF THE INVENTION 
Thus it is an object of the present invention to provide an automatic crab 
leg shell cutting-in machine which is completely free of the foregoing 
drawbacks and where the cutting-in operation is performed at an improved 
efficiency with the result that the content (crab meat) of the crab legs 
is obtained in the same configuration as that of the leg shell. 
It is another object of the present invention to provide an automatic crab 
leg shell cutting-in machine which has an excellent compatibility with 
regard to the size, length and configuration of crab legs to be processed 
by using rotary cutting-knives and at the same time enlarging or reducing 
the clearance between upper and lower feed belts in accordance with the 
dimensional conditions of the crab legs. 
SUMMARY OF THE INVENTION 
To accomplish the aforementioned objects of the present invention there is 
provided a new and unique automatic crab leg shell cutting-in machine for 
processing leg shells of crab. which are charged into a cutting-in section 
at a predetermined rate, characterized in that upper and lower feed-belts 
are provided in the longitudinal direction of the machine in such a manner 
that rotary cutting-knives are arranged therebetween on both sides of the 
cutting-in section and depressing plates are used to depress the upper and 
lower feed-belts and are located oppostie each other in such a manner that 
the upper and lower feed-belts have an increased or decreased clearance 
therebetween in the cutting-in section depending on the dimensional 
conditions of crab legs to be processed, wherein said depressing plates 
are held so as to be vertically displaced by means of resilient members or 
shock absorbing members and moreover said rotary cutting-knives are 
adapted to approach toward the longitudinal axis of the feed-belts or move 
away therefrom owing to the cooperative function of the resilient members 
or shock absorbing members and bell cranks. 
It is preferable with the present invention that the rotary cutting-knives 
which are arranged on both sides of the cutting-in section are constructed 
in the form of disc having a cutting-edge along the periphery thereof. 
Preferably, the rotary cutting-knives are constructed in the form of discs 
having a serrated cutting-edge along the periphery thereof. 
It is preferable that the upper and lower feed-belts in the form of endless 
belt have slip preventive rugged surfaces. Although, an endless belt 
having no slip-preventive-means is also acceptable. 
The depressing plates are made of any suitble material, such as, metal, 
plastic etc., as far as it is capable of depressing the feed-belts as 
required. In view of mechanical strength and friction between the 
depressing plate and feed-belt metallic material is most preferable. 
It is preferable that means for holding the depressing plates be so 
constructed that the upper and lower feed-belts have an increased or 
decreased clearance therebetween in accordance with the dimensional 
conditions of crab legs supplied into the clearance. For instance, the 
depressing plates may be held by means of resilient member, such as a coil 
spring or shock absorbing member such as a hydraulic damper which is 
arranged at the both ends or at the central part thereof. In practice it 
is most preferable that the depressing plate is pivotally secured to one 
end of bell crank. 
In order to prevent the crab legs being processed or the processed crab 
legs from being thrown away from the upper and lower feed-belts there are 
provided U-shaped guide members which are made either of metal or of 
plastic or the like material. In view of mechanical strength to be given 
to the guide members, metallic material is most preferable. 
The invention as well as other objects and advantages thereof will be more 
apparent from the following detailed description and the accompanying 
drawings, in which:

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION 
Now the present invention will be described in a greater detail with 
reference to the accompanying drawings which illustrate a preferred 
embodiment of the present invention. 
The machine of the invention is housed in a housing frame 10. 
Specifically, said housing frame 10 comprises four support legs 11 through 
14 made of angle steel, a top plate 15 fixedly secured to said support 
legs 11 through 14 at their upper ends by welding, an intermediate shelf 
16 and a reinforcement shelf 17 fixedly secured to them at their lower 
ends by welding. 
Also used in the invention is an upper endless feed-belt 18, of which one 
end portion is supported by means of a tail pulley 20 rotationally 
disposed on an upper take-up support 19 on the feeding side and other end 
portion is supported by means of a driving pulley 22 rotationally disposed 
with the aid of a pillow block 21 on the delivery side. 
Likewise, there is a lower endless feed-belt 23 which has a length a little 
longer than the upper feed-belt 18 on the both feeding and delivery sides. 
Said lower feed-belt 23 is supported by means of a tail pulley 25 
rotationally disposed on a lower take-up support 25 on the feeding side at 
one end portion and by a driving pulley 27 rotationally disposed with the 
aid of a lower pillow block 26 on the delivery side at its other end 
portion. 
Adjustment bolts 28 and 29 serve to pull the tail pulleys 20 and 25 in the 
axial direction so that the upper and lower feed-belts 18 and 23 are 
loosened or tightened by operating said adjustment bolts 28 and 29 (see 
FIG. 1). 
Take-up plates 30, 31 are fixed to the housing frames 11 and 12 of the 
machine on the feed side. The lower plate has a longer projection than the 
upper plate. The respective take-up plates 30 and 31 are provided with 
said upper take-up support 19 and the lower take-up support 24 secured 
thereto. These supports 19 and 24 support the take-up pulleys. 
Vertically arranged on each side of the upper and lower feed-belts 18 and 
23 is a cylindrical bearing box 32. Bearing box 32 has a shaft 33 which 
has a rotary cutting-knife 35 fixedly secured thereto via a washer 34 at 
its upper end and further has a secondary pulley 36 at its lower end 41. 
On the periphery of the bearing box 32 is a bell crank 37 of which one end 
is welded thereto. Also, the horizontal bell crank 37 is formed with a 
gear segment 39 at its other end which is integral to its hollow shaft 38 
(see FIGS. 1 and 4). 
Said hollow shaft 38 is rotationally supported on a pivotal pin 40. 
Further said pivotal pins 40 are fixed to a support member (not shown) at a 
predetermined distance therebetween, which is mounted in the form of 
inverted U-shape between the intermediate support-shelves 16. 
A horizontally extending adjustment bracket 42 secured to the inner side 
wall of the bell crank 37. As apparent from the drawings, said adjustment 
bracket 42 has a short vertical extension 43 which has a threaded hole 44, 
but it is to be noted that the threaded hole 44 is provided only on one of 
the bell cranks 37. A long adjustment bolt is screwed in the threaded hole 
44, until its top end abuts against the vertical extension 43 of the other 
bell crank 37 (not shown), whereby any collision between the rotary 
cutting-knives 35 of the cylindrical bearing boxes 32 and excessive 
cutting-in of the cutting edge of the rotary cutting-knives 32 is 
satisfactorily prevented (see FIG. 3). 
An attachment piece 45 is welded to the outer wall of the cylindrical 
bearing box 32. Said attachment piece 45 has a bolt 46 screwed 
therethrough and a coil spring 47 is horizontally disposed between the top 
ends of said bolts 46. 
Owing to the arrangement of the bolts 46 and coil spring 47 it is ensured 
that the both rotary cutting-knives 35 are always located in position 
between the feed-belts 18 and 23 in such a manner that they are spaced 
from the longitudinal axis of the feed-belts according to the dimensional 
conditions of crab legs to be processed. 
A pair of vertically operating bell crank members 48 are disposed above and 
below the feed-belts 18 and 23 on the feeding side of the cutting-in 
section, said bell cranks 48 having a depressing member 49 secured to one 
end thereof and further have a rectangular plate 50 secured to the other 
end thereof. 
The rectangular plates 50 are formed with gear teeth along the circular 
edges which are in engagement with each other and are pivotally supported 
by means of a support member 52 with the aid of a pivotal pin (not shown) 
which extends through a drilled hole 51 opened in position on the 
rectangular plate 50. 
The support member 52 is secured to a vertical plate 53 of which both ends 
are fixed to the intermediate support shelf 16 and top plate 15 and 
projects inwards therefrom in the form of a hook. 
Fastened in the side wall of the bell crank member 48 are set-screws 54. 
These set screws 54 serve to anchor a vertically extending coil spring 55. 
Secured to the side wall of the bell crank members 48 are attachment 
pieces 56. The attachment pieces 56 have a vertically extending adjustment 
member 57 fastened therethrough so that escessive depressing is prevented 
by the upper and lower feed-belts 18 and 23 in the cutting-in section. 
The feed-belts are depressed by means of a depressing plate 58. The 
depressing plate 58 is provided with an inclined piece at the other end 
and is adapted to be depressed by means of a depressing roller 60 arranged 
at the front end of the vertically operating bell crank 59 on the delivery 
side of the cutting-in section. 
A pair of rectangular plates 61 are secured to the bell cranks 59 on the 
delivery side and formed with gear teeth along the circular edges in 
engagement with each other. Further the bell cranks 59 are provided with 
attachment pieces 62 fixed to the side wall thereof which has a vertically 
extending adjustment member 63 fastened therethrough so that excessive 
depressing is prevented for the upper and lower feed-belts 18 and 23 in 
the cutting-in section. 
The reference numerals 64 designate a set-screw secured to the side wall of 
the bell cranks 59. Between the set-screws 64 is disposed a vertically 
extending coil spring 65 of which both ends are anchored to the set 
screws. 
The rectangular plates 61 are pivotally supported by means of a support 
member 63' with the aid of a pivotal pin (not shown) which extends through 
a drilled hole 62'. 
The support plate 63' is secured to a vertical plate 64 of which both ends 
are fixed to the intermediate support shelf 16 and top plate 15 and 
projects inwards in the form of a hook. 
Crab seafood raw material is fed through an inlet chute which has a feed 
through. Between the front end of the feed through and the lower feed-belt 
23 is a narrow clearance. 
On the feed side of the machine, a guide member 66 is disposed on the frame 
between the cutting-in section and the inlet chute 65' and which has a 
substantially U-shaped cross section. It is to be noted that the guide 
member 66 has a width equivalent to those of the upper and lower 
feed-belts 18 and 23 and is integral with both side walls so that the 
upper feed-belt 18 is received therein. 
On the delivery side of the machine, a guide member 67 is disposed on the 
frame between the cutting-in section and the outlet chute 68. It is to be 
noted that the guide member is of shorter length than that of the guide 
member 66 on the feed side of the machine but has the substantially same 
width and side wall height as those of guide member 66. The drive means 
for the knives includes a gear box 68 with driving shafts and driving 
pulleys 69 secured thereto which serve to drive the secondary pulleys 36 
of the cutting knives 35, by means of V-belts 70. 
Also part of the drive means for the knives is a first motor 71 with a 
primary pulley 72. The gear box 68 also has a primary pulley 73. There is 
also a second motor 74 for driving the feed-belts by means of a chain 
sprocket 75. A chain sprocket 75 drives the main pulley 22 while a chain 
sprocket 77 is arranged to drive the main pulley 27. Supported by the 
pillow block 26 is a chain sprocket 78. For the lower feed belt there is a 
return idler 79. There is also a caster 80, a main switch 81, a collar 82 
for tightening the rotary knives, an end plate 83 for the cylindrical 
bearing box 32 and a nut 85 for tightening the rotary cutting knives. 
Disposed on both sides of the work station is an adjustment bolt 84 for the 
purpose of displacing the gear box forwards or backwards. This adjustment 
bolt 84 is adapted to engage a nut fixed to the frame plate. 
OPERATION OF THE INVENTION 
The operation of the automatic crab leg shell cutting-in machine is as 
follows: 
First, operators charge the inlet chute 65' with a number of crab legs and 
then they feed crab legs into the space between the upper and lower 
feed-belts 18 and 23 piece by piece manually or with the aid of a feeder 
(not shown) with the back portion of the crab leg located above and the 
belly portion of the same location below and vice versa. Now the crab leg 
moves forwards together with the travelling upper and lower feed-belts 18 
and 23 to be guided into the cutting-in section, while displacing one of 
the bell cranks 48 (on the upper side) upwards against the resilient force 
of the coil spring 55 and displacing the other one (on the lower side) 
downwards. As the crab leg enters the cutting-in section, it moves 
forwards further with its shell clamped between the upper and lower 
feed-belts 18 and 23 and the side walls of the leg shell are cut in to a 
certain depth by means of the rotary cutting-knives 35 and 35. Then after 
completion of the cutting-in operation the crab leg is discharged onto a 
receiving hopper or a belt conveyor for a subsequent processing process 
via the outlet chute 68. 
The cutting-in depth of the rotary cutting-knives 35 varies, depending on 
the thickness of the crab leg shell and is controlled within a certain 
extent of deviation with the aid of the washer 34 disposed below the 
rotary cutting-knife (see FIG. 3) and the horizontal adjustment member. 
Usually, the crab leg has an inward curved side wall the curvature of which 
varies appreciably in dependence on the position on the crab leg such as 
first leg portion, second leg portion. The cutting-in machine of the 
invention makes it possible that the rotary cutting-knives 35 are 
displaced in accordance with the curvature of the side wall of the crab 
leg to be processed, said crab leg moving together with the upper and 
lower feed-belts, so that the intended cutting-in operation is performed. 
Specifically, the rotary cutting-knives 35 arranged on the both sides of 
the cutting-in section are displaced in such a manner that they approach 
toward the axis of the feed belts or move away therefrom in cooperation 
with the horizontally extending coil spring 47 and horizontally operating 
bell cranks 37, following the circular truck about the center of the 
hollow pivotal shafts 38. 
In order to eliminate the possibility that the crab leg to be processed is 
thrown out from the upper and lower feed-belts when it is charged into the 
space between the upper and lower feed-belts in a wrong manner, the 
cutting-in machine of the invention is provided with the guide members in 
the U-shaped form. 
Owing to the arrangement that the upper and lower feed-belts have an 
increased or decreased clearance between them depending on the size and 
length of the crab leg to be processed and moreover the rotary 
cutting-knives are displaced in accordance with the curvature of the side 
shell of the crab leg, because the cutting-in lines are horizontally 
formed on the side walls of the crab shell. 
Accordingly, the present invention provides a particular advantage that 
crab meat having the same configuration as that of the leg shell is 
obtained without any danger of splitting the crab meat after the 
cutting-in operation or damaging its appearance. 
Further the present invention provides an additional advantage in that 
there is a high yield rate is ensured for processing after completion of 
cutting-in operation without any danger of reduced commercial value of the 
crab meat. 
It should be of course understood that the horizontally and vertically 
extending coil springs may be replaced with shock absorbing devices having 
the same functional properties as those of the aforesaid coil springs and 
the depressing plates secured to the vertically operating bell cranks at 
one end may be replaced with hydraulic cylinders pivotally secured to the 
housing frame.