Plastic module for a conveyor mat

A plastic module for a conveyor mat, each module comprising on both sides over the entire width a number of equidistant hinge eyes and having a closed bearing surface, the hinge eyes being coupled on a side of a module to those of a module adjoining in the longitudinal direction of the mat by means of a hinge pin. According to the invention a lip-shaped flexible member is provided in the outermost hinge eye of the module includes and extends transversely over the opening for the hinge pin into a part of the hinge eye extended to the longitudinal center of the module, where the lip-shaped member is attached to an end wall of the extended portion. The opposite end wall of the hinge eye is provided with a cam-shaped projection for cooperation with the free end of the lip-shaped member so that this member can be fixed in a position blocking the hinge pin.

BACKGROUND OF THE INVENTION 
FIELD OF THE INVENTION 
The invention relates to a plastic module for a conveyor mat which is built 
up of such modules, each module comprising on both sides a number of 
substantially equidistant hinge eyes extending over substantially the 
entire width of the module, the hinge eyes of a module being coupled 
together by a bearing surface, the hinge eyes being located on a side of a 
module between the hinge eyes of a module adjoining in the longitudinal 
direction of the mat, with the hinge eyes of both modules substantially 
being in alignment, and coupled together by a hinge pin extending through 
the hinge eyes, means being provided for locking the hinge pin with 
respect to the modules. 
Such modules are known from EP-A-0598453. A conveyor mat built up of such 
modules is used in, e.g., the packaging industry, bottling plants and the 
like, in which the mat may have a relatively large width, up to a few 
meters, and is designed as an endless conveyor mat which at the beginning 
and the end of a conveyor path passes over sprockets arranged over the 
width of the conveyor. 
To lock the hinge pin, it is known to use a clip, which is placed in a 
hinge eye of a module located on the side of the conveyor mat. To this 
end, this hinge eye, generally the outermost hinge eye on the side, is 
provided with a slot-shaped opening for receiving the clip. Such a method 
of locking is described in U.S. Pat. No. 4,832,187. 
The use of separate clips has the drawback of complicating the mounting of 
the mat, in particular when, as is the case with the known clip, the 
dimensions thereof are small. Also, the clip is awkward to detach, e.g. to 
replace a hinge pin, and involves the risk that the clip will be mislaid. 
EP-A-0652169 discloses a module in which the locking member for the hinge 
pin of a conveyor mat is integral with the module. To this end, a hinge 
eye of the module, preferably the outermost hinge eye, is provided with a 
slot-shaped opening which is formed in the hinge eye from the upper side 
of the module, which slot-shaped opening, in the condition of rest, 
includes an elongated lip-shaped element. After combining the modules to 
form a conveyor mat and after placing the hinge pins, the lip-shaped 
element can be moved from the condition of rest to a blocking position by 
pressing it from the upper side of a module via the slot-shaped opening, 
e.g. with a screw driver, downwards into the hinge eye, a cam-shaped 
element arranged in the slot-shaped opening being provided for cooperation 
with the end of the lip-shaped element to hold this element in the 
blocking position. 
Although a number of drawbacks of using separate locking elements are 
removed with the known construction, the solution described has the 
drawback that as a result of the construction proposed the hinge eye in 
which the slot-shaped opening is formed is substantially weakened, which 
adversely affects the sturdiness of the mat. A further aspect is that 
conveyor mats are also used when conveying food products for which very 
high requirements are imposed on the hygienic properties of the mat, i.e. 
the measures taken to minimize the possibility of dirt deposits and 
maximize the possibility of removing dirt deposited notwithstanding. To 
this end, the presence of slot-shaped openings and the like, in particular 
in the bearing surface of the mat which comes into contact with the food, 
is highly undesirable. 
SUMMARY OF THE INVENTION 
The object of the invention is to improve the construction of a locking 
element known from EP-A-0652169 in a manner such that it can also be used 
without any inconvenience in a conveyor mat intended for conveying food 
products, and a further object is to largely prevent a possible weakening 
of the hinge eyes of a module. 
To this end, the invention provides a module of the above type, 
characterized in that the upper surface of the module, including the upper 
side of the hinge eyes, is designed as a completely closed surface, that a 
lip-shaped flexible member is provided in an outermost hinge eye of the 
module and extends transversely over the opening for the hinge pin into a 
part of the hinge eye extended to the longitudinal center of the module, 
where the lip-shaped member is attached to an end wall of the extended 
portion, that the free end of the lip-shaped member terminates at some 
distance from the opposite end wall of the hinge pin opening, and that 
this end wall is provided with a cam-shaped projection for cooperation 
with the free end of the lip-shaped member so that this member can be 
fixed in a position blocking the hinge pin.

DETAILED DESCRIPTION 
FIG. 1 is a diagrammatic perspective view of a pair of modules which forms 
part of a conveyor mat built up, in a manner known per se, of a large 
number of such modules. 
The modules are each in one piece and are made by means of, e.g., injection 
molding. Each module comprises a number of substantially identical 
equidistant hinge eyes 10. The hinge eyes are connected together by means 
of a bearing surface 12 . Each hinge eye 10 is provided with an opening 13 
for a hinge pin 14 . The hinge eyes and openings are designed in a manner 
such that all the openings of the modules are in alignment, also when the 
hinge eyes of a pair of modules adjoining in the longitudinal direction of 
the mat engage with each other as a result of the fact that the hinge eyes 
of one module are always located between the hinge eyes of the other 
module. Thus, the width of a module is determined by the number of hinge 
eyes of which it is comprised and the length of a module by the distance 
between the central axes of the hinge eyes. 
To block the hinge pins, the outermost hinge eye 15 is always formed at one 
end of the module in a manner different from the other hinge eyes 10 . As 
clearly appears from FIG. 2 in particular, a hinge eye 15 has a hinge pin 
opening 13 within a central opening 23 with an extended portion 16 which 
extends in a direction towards the longitudinal center of the module. At 
the end wall 16' of the extension 16 a lip-shaped member 17 is formed 
integral with the module, which member preferably has substantially the 
same width as the hinge eye 15 . Formed at the wall 13' of the hinge pin 
opening opposite the end wall 16' is a cam-shaped member 18 for 
cooperation with the free end of the lip-shaped member 17 to lock it in 
the opening in a manner such that a hinge pin 13 is blocked. In the 
left-hand module in FIG. 1, the lip-shaped member 17 is shown in the 
locked position. 
To ensure that during use of the mat the hinge pin does not bend or damage 
the lip-shaped member 17, the free end of this member is preferably 
provided with a notch 19 of which, seen in the Figure, the upper surface 
cooperates with the cam-shaped member 18, and of which, seen in FIG. 2, 
the wall portion located in the plane of the paper forms a stop surface 
which, in use, comes to lie against the, again seen in the FIG. 2, back 
face of the cam-shaped member. Thus, the pressure which may be exerted by 
the hinge pin is absorbed by the back face of the notch 19, which wall 
portion transfers this pressure to the cam-shaped member. 
When placing a hinge pin, the lip-shaped member 17 can be pressed slightly 
downwards to allow the hinge pin to pass through the hinge pin opening 13 
. By placing a screw driver between the, seen in the Figure, lower side of 
the lip-shaped member 17 and the wall portion 13" of the hinge eye, the 
lip-shaped member can be brought into the locked position behind the cam 
18 . When, if desired, removing the hinge pin, the free end of the 
lip-shaped member 17 is pressed out of the locking position behind the cam 
18 by means of, e.g., a screw driver, which is placed against the wall 
portion 16, after which the hinge pin can be removed. 
It is observed that when the mat only has the width of one module, this 
module may have at both ends a hinge eye 15 with a lip-shaped member 17 . 
It will be clear from the Figures that the invention provides a blocking 
member for the hinge pins of a conveyor mat, which may be formed integral 
with a module for the mat, while at least the upper surface of the module 
remains completely closed, which has the result that the mat is very 
suitable for hygienically conveying food products and is easy to clean. 
Another advantage of the invention is that the strength of the hinge eye 
15 is not influenced because it is composed in the transverse direction of 
the module of the same amount of plastic material as the hinge eyes 10 .