Sheet separating device for a sheet counting apparatus

The disclosure relates to sheet separating device for a stack counting apparatus including a counting head to traverse a corner of a stack and having a horizontal suction blade with a suction orifice on its upper surface for insertion in the stack and oscillatable about a horizontal axis to separate a corner of a sheet in the stack adhered by the suction port to the blade from the next sheet. A wiping pin is driven in an elongate orbit around the blade from the trailing edge thereof over the upper surface to the leading edge and along the underside of the blade to transfer a corner of a sheet adhered to the upper surface of the blade from the upper surface to the lower surface. A counting device is arranged to count the number of sheets transferred by the pin. In order to minimize damage to the stack by the engagement of the blade and pin in the stack, the path of the movement of the pin from the upper surface to the lower surface adjacent the leading edge of the blade is in a generally vertical direction after which the pin moves generally horizontally close to the underside of the blade, while the blade remains substantially horizontal and the blade tilts downwards to separate the corner of a sheet on it from the sheet above only after the pin has moved beyond the undersurface of the blade. The pin then moves over the upper side of the blade towards the leading edge thereof as the blade returns to the horizontal.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a sheet separating device for use, for example in 
a sheet counting apparatus. 
2. Description of the Prior Art 
A sheet separating device for use in apparatus for counting a stack of 
sheets comprising a counting head which in use is traversed along a corner 
of the stack and has a separating device comprising a suction blade 
provided with a suction orifice for insertion in the corner of the stack, 
which blade is oscillatable about a horizontal axis to separate a corner 
of a sheet in the stack adhered by suction to one side of the blade from 
the next sheet, and a wiping pin movable in an elongate orbit around the 
blade to transfer the corner of the sheet from one side of the blade to 
the opposite side thereof together with means to count the number of 
transfer operations effected. 
U.K. Patent Specification Nos. 1346749, 1426523, 1455108, 1455109 and 
1455110 all describe and illustrate examples of such counting machines. 
The blade/pin movements of all the arrangements shown in these 
specifications force a wide separation angle between adjacent sheets in 
the stack which tends to cause damage to the sheets particularly when 
counting thicker sheets which tend to be permanently creased as a result 
of the action of the pin/blade in the corner of the stack. 
It is an object of this invention to provide a sheet separating device for 
use in a sheet counting machine in which damage to the sheets as a result 
of the action of the blade/pin in the stack is avoided or minimised. 
SUMMARY OF THE INVENTION 
The invention provides a sheet separating device for a sheet counting 
apparatus comprising, a horizontally extending blade having a leading edge 
for insertion in a corner of a stack of sheets and a trailing edge, means 
to rotate the blade between a horizontal attitude and a position in which 
the blade is downwardly inclined towards the trailing edge thereof, 
suction means on the upper side of the blade, to adhere a corner of a 
sheet to the upper side of the blade, a wiper pin extending parallel to 
the blade and means to move the pin in an orbit around the blade from the 
trailing edge thereof over the upper surface to the leading edge and along 
the underside of the blade to transfer a corner of a sheet adhered to the 
upper surface of the blade by said suction means from the upper surface to 
the lower surface, the path of movement of the pin from the upper surface 
to the lower surface adjacent the leading edge of the blade being in a 
generally vertical direction after which the pin moves generally 
horizontally close to the under side of the blade whilst the latter 
remains substantially horizontal, the blade tilting downards after the pin 
has moved beyond its under-surface and the pin then moving over the upper 
side of the blade towards the leading edge thereof as the blade returns to 
the horizontal. 
Since the pin moves out of the stack horizontally immediately below the 
blade when the latter is also horizontal, the deflection of the stack and 
therefore damage to the stack is minimised.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The drawings illustrate a sheet separating device for an apparatus for 
counting a vertical stack of sheets comprising a vertically extending 
mechanism on which the sheet separating device is mounted and is traversed 
up a corner of the stack to separate one by one and to count the sheets of 
the stack. The mechanism for supporting and traversing the sheet 
separating device up the corner of the stack and for counting the 
separated sheets is generally as described and illustrated in our U.K. 
Pat. No. 1426523 to which reference should be made. The mechanism for 
actually separating corners of individual sheets in the stack as part of 
the counting operation will now be described in detail with reference to 
the drawings. 
The separating device comprises a generally rectangular base 10 having 
upstanding side walls 11, 12 extending parallel to one another along the 
sides of the base. The front end indicated generally at 9 on FIGS. 2 and 3 
lies immediately adjacent to the corner of the stack to be counted in use 
and a horizontally extending blade 13 is mounted on the side wall 11 to 
engage in the corner of the stack and a parallel pin 14 is mounted on the 
side wall 12 to pass sheets one after another from one side of the blade 
to the other. Referring to FIG. 4 of the drawings, the blade 13 is shown 
in greater detail and, as can be seen, is mounted in cantilever fashion on 
a drum 15 by means of a fixing bolt 16. 
The blade 13 has a leading edge 17 which extends into a corner of the stack 
of sheets to be counted as indicated in chain line at 18. The trailing 
edge of the blade is indicated at 19. The blade is a flattened tube having 
a cavity 20 therein which communicates through the drum with a source of 
vacuum (not shown). At the centre of the blade adjacent the leading edge 
thereof, there is a generally triangular shaped recess 21 in the upper 
surface of the blade and a suction hole 22 is formed in the bottom of the 
recess opening into the cavity 20. Suction force at the hole 22 causes a 
corner of a sheet of the stack above the blade 13 to be adhered to the top 
surface of the blade. 
Reference is now made to FIG. 5 and to FIGS. 6 to 29 which illustrate 
collectively and individually respectively the path of movement and speed 
of the pin around the blade in steps equivalent to 15.degree. of advance 
of the pin around the blade axis. 
The blade 13 is oscillated through an arcuate path in the corner of a stack 
of sheets to be counted about an axis 24 at the centre of the radius of 
the leading edge of the blade by means of a mechanism to be described 
later. When the pin is in the position shown in FIG. 6, the pin is about 
to commence wiping the corner of one sheet adhered to the top surface of 
the blade from the upper side to the lower side and the blade has almost 
reached the horizontal position the pin accelerated in this phase of its 
movement to pass downwardly generally vertically close to the leading edge 
of the blade 13. At the same time the blade 13 continues to pivot upwardly 
until it reaches the full line position shown in FIG. 9 in which it is 
angled about three degress above the horizontal. By this time the sheet on 
the blade will have been wiped to the lower side of the blade and the 
suction port in the blade will adhere the next corner above to the blade. 
Meanwhile the rapidly accelerating pin moves downwardly below the level of 
the blade and then outwardly from the stack generally horizontally at high 
speed to reach the position of FIG. 18 in which the pin is clear of the 
trailing edge of the blade. As soon as the pin has cleared the trailing 
edge of the blade, the blade 13 drops rapidly down to the lower position 
indicated in FIG. 5 and drawing with it the corner of the sheet adhered to 
it. The pin then commences its movement into the stack at a relatively low 
speed over the upper surface of the downwardly inclined blade and as the 
pin moves over the upper surface of the blade, the blade starts to rise 
again until the pin reaches a position over the leading edge of the blade 
and the blade is almost in the horizontal position thus completing the 
cycle. 
It will be seen from FIGS. 6 to 31 that the blade is in fact horizontally 
or approximately horizontally for some 180.degree. of the cycle of the 
movement of the pin around the blade. This is achieved by swinging the 
blade downwardly as rapidly and as late as possible in its cycle of 
movement in relation to the pin and by returning the blade to the 
horizontal position as soon as possible in its cycle in relation to the 
pin. The blade is thus held in the horizontal position for as long as 
possible in the cycle to ensure a good suction grip on the sheet above. 
It will also be noted that the pin moves closely adjacent the leading edge 
of the blade and it moves downwardly past the blade and the blade is held 
horizontally so that the pin can move outwardly from the stack in the 
horizontal direction. In this way deformation of the stack due to the 
action of the pin in the stack is minimised thus minimising damage to the 
corner of the sheets in the stack being counted. 
The actual counting of sheets takes place as the pin moves through the 
positions of FIGS. 23 and 24 and is effected by conventional counting 
mechanism. The mechanism for pivoting the blade 13 as described is best 
seen in FIG. 3 of the drawings to which reference will now be made. The 
drum 15 is pivotally mounted on a shaft 23 mounted for rotation in the 
side wall 11 about an axis of rotation indicated 24 which lies at the 
centre of the leading edge radius of the blade. The shaft 23 is oscillated 
by a crank arm 25 which is pivotally connected at one end of a link 26. 
The other end of the link 26 is pivotally connected to a further link 27 
which is pivotally connected to a link 28, pivotally mounted at 29 on the 
wall 11. A crank shaft 30 (see FIGS. 1 and 2) is rotatably mounted on the 
wall 11 and is driven by a pulley 31 connected by a drive-belt 32 from an 
output pulley 33 on a drive-shaft 34 of an electric motor 35 mounted at 
the rear of the base 10. The crank shaft 30 carries, on the inside of the 
wall, an eccentric mounting pivot 37 connected to the aforesaid link 27. 
As the eccentric pivot 37 of the crank shaft 30 rotates, the linkage 25, 
26, 27, 28 causes the blade 13 to pivot about the axis 24 as described and 
illustrated earlier. 
The mechanism for moving the wiper pin 14 in synchronism with the blade 13 
will now be described. 
A further output pulley 40 on the motor shaft 34 drives a pulley 41 on the 
crank shaft 42 mounted on the wall 12 through an endless belt 43. The 
pulley 41 in addition to driving the crank shaft 42 also has a gear wheel 
44 which meshes with a further gear wheel 45 on a further crank shaft 46 
mounted on the wall 12. The contra-rotating crank shafts 42, and 46 have 
crank pins 49, 54 both disposed on the inner-side of the wall 12. The 
crank shaft eccentric pin 49 is connected by a link 50 via a common pivot 
50a to a floating link 51; and, pivot 50a is also connected to further 
link 52 pivotally mounted at 53 on the wall 12. The eccentric pin 54 of 
crank-shaft 46 has one end of a lever 55 pivotally mounted thereto and the 
lower end of floating link 51 is pivotally connected at 56 partway along 
the lever 55. The outer end of the lever 55 carries the wiper pin 14. The 
crank drive mechanism for the pin and blade are constructed to cause the 
pin and blade to follow the paths of movement of the pin and blade 
indicated in FIGS. 5 to 29.