Shaft coupling

A shaft coupling, preferably for coupling a journal of a shaft of a print roll to a primary shaft, includes coupling parts which engage one another in an interlocking manner, and which are connected to the shafts to be coupled to one another. A stud projects beyond the periphery of a journal on the end of one shaft and can be pushed into a centering cutout arranged on a sleeve provided on the end of the other shaft and can be fixed there by means of a bearing surface provided in a slide ring which can be pushed over the sleeve.

FIELD OF THE INVENTION 
The invention pertains to a shaft coupling, preferably for coupling a 
journal of a shaft of a print roll to a primary shaft, with coupling parts 
which engage with one another in an interlocking manner, which are 
connected to the shafts to be coupled to one another. 
BACKGROUND OF THE INVENTION 
Shaft couplings of this type are known, for example, from EP 0392323 A1 
which corresponds to U.S. Pat. No. 5,137,495. These couplings are used, 
for example, in multicolor printing machines. In multicolor printing 
machines, the rollers of the individual printing groups are driven by 
primary shafts, where a shaft coupling is arranged between each primary 
shaft and each journal of a shaft of a print roll. The print rolls 
respectively are carried in a corresponding lateral frame. The 
construction of the known shaft coupling necessitates that in order to 
replace the printing cylinders, the latter must be withdrawn in the 
direction of their shafts from the lateral frame. This leads to a costly 
construction, since the roller must be withdrawn through the lateral 
frame. Also, the handling associated with replacement of the print roll is 
complicated and costly. 
SUMMARY OF THE INVENTION 
It is the purpose of the present invention to make available a shaft 
coupling that enables a simpler replacement of the print roll. 
This problem is solved according to the invention in that, for a shaft 
coupling of this generic type, a stud projects beyond the periphery of a 
journal on the end of a shaft and can be pushed into a centering cutout 
arranged on a sleeve, provided on the end of the other shaft and running 
perpendicular to the axis of the shaft, and can be fixed there by means of 
a bearing surface provided on a slide ring which can be pushed over the 
sleeve. This construction enables the roller to be inserted into the 
lateral frame from the side. Here, corresponding slots to which the 
centering cutout of the sleeve must be aligned are all that need be 
provided in the lateral frame in order for one to be able to insert and 
couple the print roll. The connection between the print roll and primary 
shaft is then produced by pushing over the slide ring, causing the bearing 
surface to rest against the projecting stud by this means. 
Accordingly, two sides of the stud can project beyond the journal and both 
ends can feature beveled surfaces at the respective peripheral sides. In 
addition, the stud can be twisted slightly relative to the journal. This 
ensures that when the slide ring is pushed over, the beveled surfaces of 
the stud are supported in the slide ring with the stud precisely in the 
correspondingly beveled bearing surface. 
According to a further preferred configuration, a spring-loaded piston, to 
which the slide ring is connected, can be arranged in the sleeve. The 
slide ring which is rigidly connected to the piston is also acted upon by 
means of a corresponding compression spring which acts upon the piston. At 
the same time, the slide ring is retained in the closed position over the 
sleeve by means of spring force. The piston can be withdrawn against the 
spring force by means of a corresponding connecting rod, which can be part 
of a piston-cylinder unit, so that the slide ring can be simultaneously 
withdrawn from the closed position of the coupling into the open position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 shows the incorporation, within a printing machine, of a shaft 
coupling (10) according to the invention. Here, a printing cylinder (12) 
of a multicolor printing machine is carried in lateral frames (14,16). The 
lateral frame (16) is connected by means of a crosshead (18) to a linkage 
(20). The coupling (10) is arranged between the lateral frame (16) and 
linkage (20). 
The construction of the coupling (10) according to the invention is shown 
in FIGS. 2 and 3. In FIGS. 2a and 2b, the part of the coupling which is 
arranged on the shaft (22) of the print roll (12) is represented. The 
coupling is composed of an adapter (24), which passes into a journal (26) 
of smaller diameter. A transverse hole (28) is formed in the journal (26), 
a stud (30) is placed through the transverse hole and its two sides 
project beyond it, as shown in FIG. 2b. The respective ends of the stud 
(30) feature beveled surfaces (32) on the respective opposing sides, which 
are beveled in the axial direction of the journal (26), as can be seen, 
for example, in FIG. 2a. A through-hole (34) is also provided in the stud 
(30); the hole is engaged by a pin (36) which is driven in from the end of 
the journal (26) as shown in FIG. 2b. The drilled hole (34) in the stud 
(30) has a slightly greater diameter than the pin (36), so that the stud 
(30) as a whole can be rotated slightly relative to the journal (26). 
The construction of the section of the coupling (10) developed at the 
primary shaft (38) is shown in FIGS. 2c and 2d. A flange (42) of a sleeve 
(44) is connected to an end flange (40) of the primary shaft (38). The end 
of the sleeve (44) features a fork-shaped piece (46) with a centering 
cutout (48). The centering cutout (48) runs perpendicular to the central 
axis of the sleeve (44) or primary shaft (38). Carried to be movable on 
the sleeve (44) is a slide ring (50), shown by itself in FIG. 2d and in a 
pushed-on position in FIG. 3. The slide ring likewise features a cutout 
(52) with a bearing surface (54), where the cutout (52) is, in essence, 
aligned to be perpendicular to the cutout (48). A through-hole (56) is 
also formed in the slide ring (50). 
As shown in the section in FIG. 2c, a movable piston (58), in which a 
through-hole (60) is formed travels in the sleeve (44). Running through 
the through-hole (60) is a stud, not represented in greater detail, which 
runs through the through-holes (56) of the slide ring (50), as well as 
through a slot (62) within the sleeve (44) (compare FIG. 3). Hence, the 
slide ring (50) is connected to the movable piston mounted in movable 
fashion within the sleeve by means of the stud, not represented in greater 
detail. End positions for the piston (58) as well as for the slide ring 
(50) are defined by means of the slot (62), in connection with the stud, 
not represented in greater detail. The slide ring (50) can be moved, 
together with the piston (58), in the direction of the double arrow (b) 
(see FIG. 3). Here, one of the end positions, which occurs through a stud 
(not represented) and comes to rest at the left side of the slot (62), as 
shown in FIG. 3, is the closed position of the slide ring and of the 
coupling, in which the bearing surface (54) rests against one of the 
beveled surfaces (32) of the stud (30), as is shown in FIG. 1. The 
opposing bearing surface of the slot (62) establishes the open position of 
the slide ring (50). 
In the embodiment represented here, a connecting rod (64), which first runs 
through the sleeve (44) and then through the primary shaft (38) of hollow 
form, is joined to the piston (58) running within the sleeve (44), and, as 
represented in FIG. 1, is guided out laterally. The free end of this 
connecting rod (64), guided out laterally, is connected to a 
piston-cylinder unit, not represented in greater detail. As shown in FIG. 
2c, a compression spring (66), arranged parallel to the connecting rod 
(64), bears against the piston (58) at one end and, at the other end, 
against limit stops (68), is provided within the primary shaft (38). 
Therefore, the compression spring (66) can press the piston (58), and thus 
the slide ring (50), into the closed position, as represented in FIG. 1. 
The piston (58), and thus the slide ring (50) can be moved in the 
direction of the arrow (a) according FIG. 1 against the force of the 
compression spring (66) by means of the piston-cylinder unit, (100). 
Hence, this creates a simple automatic closing mechanism.