Apparatus for transferring substantially round, fragile articles, such as for instance eggs

An apparatus for transferring substantially round, fragile articles, such as for instance eggs, from a first conveyor to a second conveyor or vice versa, characterized in that the transfer takes place by means of a swivel lever according to a flowing path of movement, wherein in the starting point or end point respectively of the path of movement, the velocity and direction of movement of the article to be transferred correspond to the velocity and direction of movement of the first conveyor and wherein the velocity and direction of movement of the article in a transfer track correspond to those of the second conveyor.

The invention relates to an apparatus for transferring, in a transfer area, 
substantially round, fragile articles, such as for instance eggs or the 
like, from a first conveyor to a second conveyor or vice versa. 
Such apparatus is described in European patent EP-A-0 588 412. A drawback 
of the known apparatus is that the capacity thereof is limited in that the 
articles are subjected to fairly abrupt changes of movement and velocity. 
In the known apparatus, a number of eggs are lifted, by means of a fork, 
from support elements and moved via this fork to the second conveyor, 
which is provided with grippers that are each adapted to pick up one 
article. To provide that the picking up of eggs by means of the fork is 
established in a controllable manner, it is necessary that the support 
elements on which the eggs are located be moved intermittently. Such 
intermittent movement requires that the eggs located on the support 
elements be accelerated and decelerated each time, which also has an 
adverse effect on the velocity of the machine, as the eggs must not fall 
from the support elements during this acceleration and deceleration. 
Moreover, accelerating and decelerating the support elements results in 
undesired machine vibrations. Further, the known apparatus has the 
drawback that the articles should first be transferred from the support 
element onto the fork, after which they are placed from the fork into a 
gripper again. Hence, essentially two transfer operations are involved 
that are each quite critical and entail the chance of breaking of the 
article to be transferred. 
The object of the invention is to provide an apparatus of the type 
described in the opening paragraph, in such a manner that the 
above-described drawbacks do not occur. 
The apparatus of the type mentioned in the opening paragraph is 
characterized in that the first conveyor comprises a number of support 
elements that are each adapted to carry one article, which first conveyor, 
at the location of the transfer area, moves at a first continuous velocity 
in a first conveying direction, wherein the second conveyor comprises a 
number of grippers that are each adapted to pick up one article, which 
second conveyor, at the location of the transfer area, moves at a second 
continuous velocity in a second conveying direction, wherein the second 
conveyor, at the location of the transfer area, extends above the first 
conveyor and the first and second conveying directions include an angle 
.beta. relative to each other, wherein each support element is connected 
via at least one swivel lever to the first conveyor, wherein each swivel 
lever is connected to a cam follower, wherein adjacent the transfer area a 
cam track is disposed adapted to cooperate with the cam followers to 
realize a swivel movement of the swivel levers, so that as a result of 
this swivel movement, the support elements move through a continuous and 
flowing path of movement, wherein the velocity and direction of movement 
of each support element in a starting point and end point of the path of 
movement correspond to the velocity and the conveying direction of the 
first conveyor, wherein the velocity and direction of movement of each 
support element at the location of a transfer track, where the article is 
transferred from the support element into a gripper of the second conveyor 
or vice versa, substantially correspond to the velocity and conveying 
direction of that relevant gripper. 
In an apparatus of such design, the articles move through a continuously 
formed path of movement during the transfer from a support element of the 
first conveyor to a gripper in the second conveyor. The article to be 
transferred moves through this path of movement without undergoing any 
abrupt changes of velocity, so that the accelerations experienced by the 
article are minimal and the path can be moved through at high velocity, so 
that a particularly high transfer capacity can be established. Moreover, 
for the purpose of the transfer of the article, no intermediate transfer 
takes place, as is the case in the prior art. In one single movement, the 
articles are placed from the support elements of the first conveyor into 
the grippers of the second conveyor, so that only one transfer operation 
is necessary, so that the risk of breaking and/or loss of the article is 
limited to the absolute minimum. Because at the location of the transfer 
track, where the article is transferred from the support element into a 
gripper of the second conveyor or vice versa, the velocity and the 
direction of movement of a relevant support element substantially 
correspond to the velocity and conveying direction of an associated 
gripper, the transfer of the article from the support element to the 
gripper is particularly even and shockfree. 
To create such path of movement, according to a further elaboration of the 
invention, each swivel lever is pivotable about a pivotal axis extending 
in a horizontal plane, wherein, during the swivel movement, each swivel 
lever is always in an imaginary vertical plane which extends 
perpendicularly to the pivotal axis and moves at a velocity and in a 
direction corresponding to the velocity and the conveying direction of the 
first conveyor, wherein the imaginary plane and the first conveying 
direction include an angle .alpha. relative to each other, wherein the 
tangent of this angle .alpha. meets the formula: 
##EQU1## 
wherein: V1 is the conveying velocity of the first conveyor; 
V2 is the conveying velocity of the second conveyor; and 
.beta. represents the angle between the first and the second conveying 
direction in the transfer area. 
When the angle .alpha. is chosen so that the tangent thereof meets the 
above formula, it is possible to impart to the support elements, by a 
simple swivel movement of the lever, a direction of movement and a 
velocity corresponding to the second conveying direction and the second 
velocity. For this purpose, according to a further elaboration of the 
invention, the product of the angular velocity of the swivel movement at 
the location of the transfer track and the length of each swivel lever 
should substantially meet the following formula: 
##EQU2## 
wherein: .omega. is the angular velocity of the swivel arm at the location 
of the transfer track; 
L is the length of the swivel arm; 
.alpha. represents the angle which the first conveying direction includes 
with the vertical plane in which the swivel arm swivels; 
.beta. represents the angle which the first conveying direction includes 
with the second conveying direction; and 
V2 is the conveying velocity of the second conveyor. 
The angular velocity .omega. is determined by the form of the cam track and 
the velocity V2 of the first conveyor.

FIG. 1 shows an exemplary embodiment of the apparatus according to the 
invention for transferring in a transfer area substantially round, fragile 
articles, such as for instance eggs, fruit, tomatoes, light bulbs or the 
like. The apparatus comprises a first conveyor 1 and a second conveyor 2. 
The first conveyor 1 comprises a number of support elements 3, each 
adapted to carry one article. At the location of the transfer area 4, the 
first conveyor 1 travels in a first conveying direction X at a first 
continuous velocity V1. The second conveyor 2 comprises a number of 
grippers 5, each adapted to pick up one article. At the location of the 
transfer area, the second conveyor travels in a second conveying direction 
Y at a second continuous velocity V2. At the location of the transfer area 
4, the second conveyor 2 extends above the first conveyor. The first and 
second conveying directions X and Y include an angle .beta. relative to 
each other. In the exemplary embodiment shown in FIGS. 1 and 2, this angle 
.beta. is 90.degree.. In the exemplary embodiment of FIG. 5, .beta. is 
less than 90.degree.. 
As is clearly shown in FIG. 2, each support element 3 is connected, via at 
least one swivel lever 6, to the first conveyor 1. Each swivel lever 6 is 
in connection with a cam follower 7 cooperating with a cam track 8 
arranged adjacent the transfer area 4. The cam followers 7 realize, in 
cooperation with the cam track 8, the swivel movement of the swivel levers 
6 in such a manner that due to this swivel movement, the support elements 
3 move through a continuous and flowing path of movement B. In a starting 
and end point P of the path of movement, the velocity and the direction of 
movement of each support element 3 correspond to the velocity V1 and the 
conveying direction X of the first conveyor 1. The point P is termed 
`starting point` and `end point` respectively, because when transfer takes 
place from conveyor 2 to conveyor 1, this point is an end point, and when 
transfer takes place from conveyor 1 to conveyor 2, this point P is a 
starting point of the path of movement B. The velocity and the conveying 
direction of each support element 3 at the location of a transfer track 9, 
where the article is transferred from the support element 3 into the 
gripper 5 of the second conveyor 2 or vice versa, and which transfer track 
9 hence forms a part of the path of movement B, correspond to the velocity 
V2 and the conveying direction Y of the relevant gripper 5 or of the 
second conveyor 2. 
As is clearly visible in FIGS. 2 and 5, each swivel lever 6 is pivotable 
about a pivotal axis 10 extending in a horizontal plane. During the swivel 
movement, each swivel lever 6 is always in an imaginary vertical plane T 
extending perpendicularly to the pivotal axis 10 and travelling at a 
velocity V1 in a direction X which corresponds to the velocity V1 and the 
conveying direction X of the first conveyor 1. The imaginary plane T and 
the second conveying direction X include an angle .alpha. relative to each 
other, with the tangent of this angle .alpha. meeting the following 
formula: 
##EQU3## 
wherein: V1 is the conveying velocity of the first conveyor; 
V2 is the conveying velocity of the second conveyor; and 
.beta. represents the angle between the first and the second conveying 
direction in the transfer area. 
When the two conveyors 1 and 2 extend perpendicularly to each other, the 
angle .beta. is 90.degree. and tangent .alpha. is hence equal to V2 
divided by V1. In the transfer track, the velocity component in 
X-direction experienced by the support elements 3 due to the swivel 
movement is equal but opposite to the first conveying velocity V1. At 
least when the above formula is met, the velocity component of the support 
elements 3 in Y-direction experienced by the support elements due to the 
swivel movement corresponds to the velocity V2. To be able to realize 
this, it is necessary that the angular velocity .omega. of the swivel 
movement and the length of the swivel lever 6 meet certain conditions 
determined by the following formula: 
##EQU4## 
wherein: .omega. is the angular velocity of the swivel arm at the location 
of the transfer track; 
L is the length of the swivel arm; 
.alpha. represents the angle which the first conveying direction includes 
with the vertical plane in which the swivel arm swivels; 
.beta. represents the angle which the first conveying direction includes 
with the second conveying direction; and 
V2 is the conveying velocity of the second conveyor. 
As is clearly visible in FIGS. 2 and 5, the support elements 3 are designed 
as dishes, with a number of dishes 3 being mounted on a dish support 11. 
The dish support 11 extends by a longitudinal center line in a horizontal 
plane and perpendicularly to the first conveying direction X, and is 
pivotally connected to two swivel levers 6. The swivel levers 6 extend 
parallel to each other in that they are each pivotally connected, via a 
pivotal axis, to the first conveyor 1, so that a parallelogram rod system 
is created. Each pivotal axis 10 of the two swivel levers 6 comprises a 
gear 12 fixedly connected thereto. The two gears 12 cooperate with a cam 
follower gear 13 which is fixedly connected to the cam follower 7 in such 
a manner that the position of the cam follower 7 determines the rotative 
position of the cam follower gear 13 and, accordingly, of the two swivel 
levers 6. The pivotal axes 10 and the cam follower gear 13 are 
bearing-mounted on a cross bar 18 of the conveyor 1, which cross bars 18 
are connected to conveying chains 16. It is readily understood that the 
swivel movement of the swivel levers 6 can also be realized in a different 
manner. For instance, the cam follower gear 13 can be replaced by a gear 
rack having a cam, or use can be made of rod systems or geared belt 
transmissions or cable transmissions. 
In general, the second conveyor 2 comprises a number of rows of grippers 5, 
which rows extend parallel to each other and in the second conveying 
direction Y. The dishes 3 of the first conveyor 1 are arranged in rows 
extending perpendicularly to the first conveying direction X, with the 
number of dish supports 11 per row of dishes 3 preferably corresponding to 
the number of rows of grippers 5 in the second conveyor 2. The apparatus 
comprises a number of cam tracks 8, which number corresponds to the number 
of rows of grippers 5 in the second conveyor. The cam tracks 8 in the 
first conveying direction are staggered in X-direction relative to each 
other. In an apparatus of such design, for instance six dishes 3 per row 
are present in the first conveyor 1, of which dishes the three on the left 
connect to a first cam follower 7 and the three on the right connect to a 
second cam follower 7. The second conveyor 2 for instance comprises two 
rows of grippers 5, extending parallel to each other in the second 
conveying direction Y. The left-hand cam track 8 is disposed so that the 
path of movement B leads to the first row of grippers 5 and a second cam 
track 8 is of such design that the three right-hand dishes 3 lead to the 
second row of grippers 5. In this manner, all kinds of combinations of 
rows of grippers 5 and rows of dishes 3 can of course be realized. 
Of course, the grippers 5 should be brought from an open position into a 
closed position or vice versa at the right moment. For this purpose, 
according to a further elaboration of the invention, a number of gripper 
cam tracks 14 are provided, which number corresponds to the number of rows 
of grippers 5 in the second conveyor 2. The grippers 5 of the second 
conveyor 2 comprise control cams 15, which at least in the transfer area 4 
cooperate with the gripper operating members 14 in such a manner that the 
grippers 5 in the transfer area 4 are brought from an open position into a 
closed position or vice versa. 
The gripper operating members can be designed as cam tracks or as 
positively excited operating members such as, for instance, a rod 
following a path which path extends in a plane perpendicular to the 
longitudinal axis of the rod, with the rod extending in the second 
conveying direction. The path is chosen so that it intersects the path in 
which the control cams 15 travel. With such a construction, a number of 
grippers can be closed or opened at the same moment. 
Reference is further made to the simplified top plan view of an exemplary 
embodiment of the apparatus in FIG. 5. In this simplified top plan view, 
the second conveyor 2 is shown in dotted lines, and the X-direction, the 
Y-direction, the angle .beta. between the two conveyors 1, 2 and the angle 
.alpha. which each swivel arm 6 includes with the first conveying 
direction X are clearly shown. Moreover, an indication of the swivel plane 
T in which the swivel lever 6 is located is shown. This swivel plane T 
moves at a velocity V1 in the X-direction along with the swivel lever 6 
and extends perpendicularly to the pivotal axis 10 of the relevant swivel 
lever 6. It is understood that when angle 3 is not 90.degree., the dish 
supports 11 during the swivel movement also have to follow an angular 
rotation of a magnitude of 90.degree.-.beta. in the horizontal plane. 
FIG. 4 shows three graphs in which the path travelled by a support element 
in the different directions is plotted out against the time. From this, it 
can clearly be observed that around the point of time 0.4, the support 
element 3 in the X-direction is temporarily stationary and that around the 
same point of time, the support element 3 is at its highest point, which 
appears from the graph for the Z-direction. At that moment, the path 
travelled in Y-direction per unit of time is virtually constant and 
corresponds to the velocity V2. After T=0.5, the transfer is completed and 
the swivel arm moves slightly further to prevent the retardation forces 
that act on the mechanism from being too great. Next, somewhere in the 
return path of the first conveyor 1, each swivel lever 6 with the 
associated dish 3 can be swivelled back again into the starting position. 
In this starting position, the dishes 3 can pick up again a next article, 
which is passed to the transfer area 4. 
It is readily understood that the invention is not limited to the exemplary 
embodiments described, but that various modifications are possible within 
the framework of the invention.