Patent Application
20070158903
In a printing operation, signatures are moved through a printing press at a maximum press speed that is considerably faster than can be accommodated in downstream equipment such as folders. Typically, signature speed is reduced by approximately 50% before input to a folder.
In known printing press equipment, a deceleration mechanism is utilized to decelerate signatures as they exit a printing press, and prior to input to a folder. The deceleration mechanism implements mechanical structures that engage and decelerate the individual signatures. The constant stress of multiple decelerations of substantial numbers of signatures, as are encountered in commercial printing operations, causes durability problems with known deceleration solutions. Moreover, in some known devices, the abrupt nature of the signature deceleration results in product defects.
The present invention provides a new and improved apparatus and method for decelerating a signature.
In a first exemplary embodiment of the present invention, an apparatus for decelerating a signature comprises a movable belt arrangement, and a motor coupled to the movable belt arrangement for controllably moving the movable belt arrangement through a cyclical velocity profile. Pursuant to a feature of the present invention, the movable belt arrangement is moved through a signature engaging section with the cyclical velocity profile causing the motor to decelerate the movable belt arrangement from a first speed to a second speed while engaging a signature in the signature engaging section. The signature enters the signature engaging section at the first speed, and leaves the signature engaging section at the second speed, lower than the first speed. The cyclical velocity profile causes the movable belt arrangement to accelerate upon the signature leaving the signature engaging section, back to the first speed, prior to a next signature entering the signature engaging section.
In a second exemplary embodiment of the present invention, a method for decelerating a signature comprises the steps of providing a movable belt arrangement, and controllably moving the movable belt arrangement through a cyclical velocity profile. Pursuant to a feature of the present invention, the cyclical velocity profile causes the movable belt arrangement to decelerate from a first speed to a second speed while engaging a signature in a signature engaging section, the signature entering the signature engaging section at the first speed, and leaving the signature engaging section at the second speed, lower than the first speed. The cyclical velocity profile subsequently accelerates the movable belt arrangement upon the signature leaving the signature engaging section, back to the first speed, prior to a next signature entering the signature engaging section.
a is a segment of the perspective view of
b is a segment of the perspective view of
FIGS. 4(a)-(e) show a side view progression of signature travel through the two-motor belt arrangement of
Referring now to the drawings, and initially to
a shows an alternative embodiment for the pins of
b shows a further alternative embodiment for the pins of
According to a feature of the present invention, the variable speed motor 1 is controlled to operate in a sinusoidal speed variation cycle, as illustrated, for example, by the solid line velocity profile curve 14 depicted in
At point 18, the speed of the motor 1 is at a minium, to match the operating speed of the downstream equipment. After discharge of the signature 8, the speed of the motor 1 is controlled to accelerate back to its maximum speed (points 18 to 20 on the graph of
Referring now to
A second variable speed motor 11 is coupled to a drive sprocket assembly 13. The drive sprocket assembly 13 is arranged to drive a second pair of belts 12 through a path defined by the drive sprocket assembly 13 and the idler sprockets 3″, 4″, 5″. A second pair of pins 6″ is provided, each one of the pair 6″ is mounted on a respective one of the belts 12 to register and align a second signature 8″ carried by the belts 12 from the idler sprockets 3″ to the idler sprockets 5″. The second pair of belts 12 is offset from and interspersed between the first pair of belts 7′ such that the pairs of belts 7′ and 12 are moved independtly from one another by the respective motors 1, 11.
According to a feature of the present invention, the variable speed motors 1, 11 are controlled to operate in sinusoidal speed variation cycles that are out of phase from one another. As noted above, the solid line velocity profile curve 14 depicted in
Similarly, the minimum velocity 18 of the curve 14, for the first motor 1, occurs at the same time as the maximum velocity 19 of the velocity curve 15 for the second motor 11, and so on. The velocity curve 14 returns to a maximum velocity, once again at point 20, at the end of a period P (21 on the graph of
FIGS. 4(a)-(e) show a side view progression of signature travel through the two-motor belt arrangement of
In
In
Finally, in
This sequence of events continues such that alternative signatures, each at a maximum speed, are engaged by pins, alternatively, of the first and second pairs of belts 7′ and 12. The belt pairs operate through alternate periods of acceleration and deceleration, 180 degrees out of phase from one another, the decelerate each of the incoming signatures, from a press speed to a slower speed suitable for operation of downstream equipment.
Referring now to
In the example of
A second motor 113 is coupled to each of a gear box 112 and the drive cylinder 109. The gear box 112 is, in turn, coupled to the drive cylinder 105. The gear ratio provided by the gear box 112 is such that the surface velocity of the drive cylinder 105 is proportionately faster than the surface velocity of the drive cylinder 109, as will also be described in greater detail below.
Each of the drive gears 103, 105, 107, 109 dives a corresponding endless belt 104, 106, 108, 110 around respective idler cylinders 120, 122, 124, 126. Moreover, a plurality of idler belt arrangements 128, 130, 132, 134 is arranged, one each in an opposed relation to a corresponding one of the endless belt 104, 106, 108, 110. A signature 111 is received between the pairs of opposed endless belts 104, 106, 108, 110 and idler belt arrangements 128, 130, 132, 134, for transport in the direction of travel indicated in
As the signature 111 exits the opposed belts 104, 128 it will be traveling at 85.4% of the entrance velocity as the signature 111 follows the velocity profile 114. The signature then enters the opposed belts 106, 130 and follows the velocity profile 115. The opposed belts 106, 130 operate to decelerate the signature further from 85.4% of the original entrance velocity, to 70.7% of the entrance velocity.
As the signature 111 travels through the opposed belts 106, 130, the belt 104 is driven to accelerate back to 100% velocity (velocity profile 114) to match the entrance velocity of a next entering signature. After travel through the opposed belts 106, 130, the signature 111 enters the opposed belts 108, 132, and decelerates from 70.7% to 60.4% of the entrance velocity, according to the velocity profile 116. Finally, the signature 111 travels through the opposed belts 110, 134 according to velocity profile 117 to further reduce the velocity to 50% of the entrance velocity. Thus, the signature velocity is incrementally reduced 50% in four stages.
Subsequent to transport of a signature, each of the driven belts 106, 108, 110 is accelerated back to the initial velocity to match the velocity of a next incoming signature. The velocity profiles 114, 116 are in phase with one another, with an offset in nominal velocity. The offset is achieved by the gearbox 102 in between the motor 101 and the driven cylinder 103. The velocity profiles 115, 117 are also in phase, but offset in nominal velocity by the gear box 112.
As noted above, the motors 101, 113101, 113 are each controlled to be operated through a sinusoidal velocity cycle and the motors 101, 113 are operated 180 degrees out of phase from one another. Additional stages can be added with either additional motors or gearboxes.
In the preceding specification, the invention has been described with reference to specific exemplary embodiments and examples thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention as set forth in the claims that follow. The specification and drawings are accordingly to be regarded in an illustrative manner rather than a restrictive sense.
