Automatic printing apparatus for a packing case carried on a conveyor belt unit

An automatic printing apparatus is used to print indentifying words on a packing case that is carried on a conveyer belt unit and includes a sensor, a lower support unit, a lengthwise-position adjustment device, an upper support unit, a height adjustment device, a feeding hydraulic cylinder, a printer support unit, a contact switch, a printing hydraulic cylinder and a printer member. The printer member is carried on the printer support unit. The printer support unit is carried on the upper support unit. The upper support unit is carried on the lower support unit. The lengthwise-position adjustment device can be actuated to adjust the position of the lower support unit along the length of the conveyer belt unit. The height adjustment device can be actuated to adjust the vertical position of the upper support unit relative to the lower support unit. When the packing case is moved to align with the sensor, the sensor activates the feeding hydraulic cylinder so as to move the printer support unit toward the packing case.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a printing apparatus, more particularly to an 
automatic printing apparatus for a packing case that is carried on a 
conveyer belt unit. 
2. Description of the Related Art 
When packing cases are moved by a conveyer belt unit to a predetermined 
position for transportation or storage, some indentifying words are 
printed manually on each of the packing cases. It is time-consuming to 
perform this manual printing process. 
SUMMARY OF THE INVENTION 
Therefore, the main object of this invention is to provide an automatic 
printing apparatus for a packing case that is carried on a conveyer belt 
unit. 
According to this invention, an automatic printing apparatus is used to 
print a packing case that is carried on a conveyer belt unit. The printing 
apparatus includes a lower support unit which is disposed movably on an 
upright side wall of the conveyer belt unit. A lengthwise-position 
adjustment device is mounted operatively on the conveyer belt unit and is 
actuatable so as to move the lower support unit along the length of the 
conveyer belt unit. An upper support unit is mounted movably on the lower 
support unit. A height adjustment device is mounted operatively on the 
lower support unit and is actuatable to move the upper support unit 
vertically on the lower support unit. A printer support unit is mounted 
movably on the upper support unit. A feeding hydraulic cylinder has a 
cylinder body fixed on the upper support unit, and a piston rod mounted 
movably in the cylinder body of the feeding cylinder body at one end 
portion thereof and connected securely to the printer support unit at the 
other end portion thereof. A sensor is installed on the side wall of the 
conveyer belt unit so as to activate the feeding hydraulic cylinder to 
move the printer support unit toward the packing case when the sensor 
detects that the packing case is at a predetermined position on the 
conveyer belt unit. A printing hydraulic cylinder unit includes a printing 
hydraulic cylinder carried on the printer support unit, and a printer 
member disposed between the printing hydraulic cylinder and the packing 
case. The printing hydraulic cylinder has a cylinder body fixed on the 
printer support unit, and a piston rod mounted movably in the cylinder 
body of the printing hydraulic cylinder at one end portion thereof and 
connected securely to the printer member at the other end portion of the 
printing hydraulic cylinder. A contact switch is installed on the front 
end of the printer support unit and is connected functionally to the 
printing hydraulic cylinder. When the contact switch is moved to contact 
the packing case, the piston rod of the printing hydraulic cylinder 
carries the printer member to move toward the packing case so as to print 
the packing case.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to FIG. 1, an automatic printing apparatus of this invention 
consists of a printing mechanism that is disposed on a side of a conveyer 
belt unit (1) which has two upright side walls (11) at two opposite sides 
thereof. A conveyer belt (2) is interposed between the side walls (11). 
The printing mechanism includes a sensor (10), a lower support unit (20), 
a height adjustment device, a feeding assembly, a contact switch (50) and 
a printing hydraulic cylinder unit (60). 
The sensor (10) is installed on a side wall (11) of the conveyer belt unit 
(1) and is connected functionally to the feeding unit. When a packing case 
is moved so as to align with the sensor (10), the sensor (10) sends a 
signal to the feeding unit in order to activate the same for printing. In 
this embodiment, the sensor (10) is an electric eye. 
A fixed plate (3) is mounted securely on the outer side of the side wall 
(11) and has a horizontal dovetail groove (310) formed in the upper 
surface thereof. 
The lower support unit (20) includes a plate body (20') and a dovetail 
tongue (21) disposed securely on the bottom surface of the plate body 
(20'). The dovetail tongue (21) is engaged within the dovetail groove 
(310) of the fixed plate (3) so as to mount the lower support unit (20) 
movably on the fixed plate (3). A lengthwise-position adjustment device 
includes a horizontal adjustment bolt (4) engaged threadably with the 
threaded hole of a lug (5) which is mounted securely on the side wall 
(11). An end of the horizontal adjustment bolt (4) is engaged threadably 
within the threaded hole of the fixed plate (3). A first hand wheel (6) is 
connected securely to the other end of the horizontal adjustment bolt (4) 
and is actuatable so as to move the plate body (20') on the fixed plate 
(3) along the length of the conveyer belt unit (1). An upper support unit 
is carried on the upper end of the height adjustment device and consists 
of a U-shaped frame (30') (see FIG. 1) and a rectangular frame which 
includes an upper horizontal bar (31), a lower horizontal bar (32) and two 
vertical guide rods (33) which interconnect the upper and lower horizontal 
bars (31, 32). The guide rods (33) extend through the guide holes (22) of 
the plate body (20'). The U-shaped frame (30') is connected securely to 
the rectangular frame. 
The height adjustment device includes a vertical adjustment bolt (34) which 
extends through the middle hole (321) of the lower horizontal bar (32) and 
the threaded hole (23) of the plate body (20'). The upper end of the 
vertical adjustment bolt (34) is engaged threadably within the threaded 
holes of the upper horizontal bar (31). A second hand wheel (35) is 
connected securely to the lower end of the vertical adjustment bolt (34) 
and is actuatable so as to move the upper horizontal bar (31) vertically 
on the lower support unit (20) between the positions shown in FIGS. 2 and 
5. 
The feeding assembly includes a printer support unit and a feeding 
hydraulic cylinder. The printer support unit consists of a horizontal 
support bar (41) and a horizontal plate (44) fixed on the top surface of 
the horizontal support bar (41). The feeding hydraulic cylinder has a 
cylinder body (43) fixed on the U-shaped frame (30'), and a piston rod 
(431) mounted movably in the cylinder body (43) at the rear end portion 
thereof and connected securely to the horizontal support bar (41) at the 
front end portion thereof. The upper horizontal bar (31) has a middle hole 
(311) through which the piston rod (431) extends. The feeding hydraulic 
cylinder can move the horizontal support bar (41) between the positions 
shown in FIGS. 2 and 3. 
The printing hydraulic cylinder unit (60) includes a printing hydraulic 
cylinder (61), a printer push plate (62) and a printer member (63). The 
printing hydraulic cylinder (61) has a cylinder body (610) fixed on the 
horizontal plate (44), and a piston rod (611) mounted movably in the 
cylinder body (610) at the rear end portion thereof and connected securely 
to the printer push plate (62) at the front end portion thereof. The 
printing hydraulic cylinder (61) can move the printer member (63) between 
the positions shown in FIGS. 2 and 4. 
The contact switch (50) is installed on the front end portion of the 
horizontal plate (44). Two horizontal guide rods (441) are fixed on the 
horizontal plate (44) and extend through the guide holes (621) of the 
printer push plate (62) so as to guide the printer push plate (62) to move 
transversely relative to the conveyer belt unit (1), thereby impelling the 
printer member (63) toward the conveyer belt unit (1) for printing. 
When it is desired to print two opposite sides of the packing case, another 
similar printing mechanism (indicated by the phantom lines in FIG. 1) may 
be provided on the conveyer belt unit (1) in such a manner that the 
printing mechanisms are located on two opposite sides of the conveyer belt 
unit (1). As shown in FIGS. 2, 3, 4 and 5, the printing mechanisms are 
similar to each other in construction and are interconnected by an 
electrical connection which is interposed between the contact switches 
(50). The electrical connection is designed so that the printing hydraulic 
cylinders (61) can be activated only when both of the contact switches 
(50) contact simultaneously the packing case (b). 
In operation, when the packing case (b) is moved to the position shown in 
FIG. 2 on the conveyer belt (2), in which the packing case (b) is located 
between the printing mechanisms, the sensors (10) send a signal to the 
feeding hydraulic cylinders so as to move the horizontal support bar (41) 
and the horizontal plate (44) toward the packing case (b) until the 
contact switches (50) contact the packing case (b). The contacts switches 
(50) activate the printing hydraulic cylinders (61) so as to move the 
printing member (63) toward the packing case (b) for printing. When the 
packing case (b) is not placed accurately on the middle portion of the 
conveyer belt (2), the contact switches (50) cannot contact simultaneously 
the packing case (b), and thus, the printing hydraulic cylinders (61) 
cannot be activated. Accordingly, the identifying words can be printed on 
two opposite sides of the packing case (b) in an orderly manner by means 
of the automatic printing apparatus of this invention. 
With this invention thus explained, it is apparent that numerous 
modifications and variations can be made without departing from the scope 
and spirit of this invention. It is therefore intended that this invention 
be limited only as indicated in the appended claims.