A pendulum-type flying shear having a speed range of a high speed to a low speed for shearing a hot rolled material having a large cross section in which there are provided vertically movable upper and lower cutting blades within a frame mounted on a crank shaft and the blades are moved towards and away from each other to shear the material while the frame is oscillated. Particularly, while the crank shaft is rotated at a constant speed, the oscillating speed of the frame is synchronized with the speed of movement of the material to be sheared and speed synchronizing apparatus including a gear device and the like is interposed between the oscillating device and the driving device so that a good shearing performance can be obtained with a small capacity of the driving device.

BACKGROUND OF THE INVENTION 
This invention relates to a shear for shearing a material during its 
movement and, more particularly, to a pendulum-type flying shear for 
shearing a material moving between vertically movable cutting blades 
within a frame mounted on a crank shaft, while the frame is subjected to 
an oscillating movement. 
In such a pendulum-type flying shear, the energy required for shearing the 
material is equal to the speed of the material passing through the shear 
multiplied by the cross-section of the material, as is same as in the 
theorem of continuity in the field of the fluid dynamics. In a specific 
shear, therefore, it will be necessary to reduce the shearing speed or the 
speed of movement of the material to be sheared, when the latter has a 
larger cross-section. 
It will, therefore, be understood that if a steplessly variable speed gear 
effective to the pendulum-type flying shear is provided therein materials 
having large and small cross-sections will be sheared by the single shear. 
However, there has never been such a steplessly variable speed gear as is 
of a large capacity, high efficiency and small and cheap type, and thus a 
direct current electric motor capable of making the speed control has 
hitherto been used to vary the shearing speed by controlling the speed of 
the motor itself. Furthermore, the speed varying operation can be achieved 
by combining a constant speed electric motor and a toothed wheel gearing, 
but such arrangement can not provide a steplessly variable speed 
transmission and the size of the speed gear and the required area of the 
installation are very large so that this system can not have been used. 
In the pendulum-type flying shear operated by the speed control system with 
the direct current electric motor, the capacity of the motor is determined 
in consideration of the following conditions: 
(i) Shearing energy or inertia energy should be generated which is required 
for shearing an allowable maximum cross-section of the material at an 
allowable minimum speed (condition to the maximum output), and 
(ii) said energy can be generated within the minimum shearing cycle (the 
shearing length divided by the maximum material speed) (the momentary 
output being large). 
In these two conditions, the second condition (ii) is closely concerned 
with the production efficiency, so that the minimum shearing cycle tends 
to become small, but, in this case, the capacity of the motor should 
become large and thus a large capacity of the motor is to be used. In case 
of using such a large capacity of the motor, however, there will be caused 
a problem that the efficiency is lowered when a large cross-section of the 
material is sheared at a low speed. This results from the fact that the 
efficiency of the motor is maximum when it is driven at the rated speed 
and lowers as it is driven at a low speed. 
In addition, as the motor capacity becomes large, the control device and 
the power source installation will become large, and the installing cost 
and running cost will also become very high. 
In the hot rolling installations, furthermore, for the purpose of recent 
improvement of the productivity and product quality, high speed and 
continuous rolling lines have been developed. As a result, it is required 
for the pendulum-type flying shear to provide a wide speed range from a 
high speed to a low speed and the shearing operation of a large 
cross-section of the material by a small power. However, as the speed of 
movement of the material becomes high and as the cross-section becomes 
large, the impact force applied to the shear when shearing operation 
becomes large, so that it becomes necessary to synchronize the shearing 
speed or the speed of movement along the line of the upper and lower 
cutting blades with the speed of movement of the material. The speed 
synchronization is an important factor in view points of not only lowering 
the impact force, but also shearing the material at the desired shearing 
position to enhance the shearing accuracy and provide a good sheared 
section. 
Hitherto, as a flying shear for shearing a strip conveyed from a hot 
rolling mill, while the strip is moving, a drum type flying shear or a 
four-link type flying shear has mainly been used. The drum type flying 
shear is arranged such that upper and lower cutting blades are secured to 
a pair of rotating drums disposed on the upper and lower sides, 
respectively, of the material, the drums being rotated at a speed 
synchronized with the material speed to shear the material bitten between 
the blades. In this type of shear, however, there are problems that the 
blades are engaged with the material with an angle of inclination relative 
to the latter so that relative sliding movement is caused between the 
blades and the material, and the blades are interfered with each other and 
the adjustment of the gap between the blades or the lapping amount is 
difficult. 
On the other hand, the four-link type flying shear is arranged such that 
two pairs of links for forming parallelograms on upper and lower sides and 
opposite sides, and upper and lower blades are secured to arms 
constituting the parallelograms and rotated in synchronous relationship 
with the speed of moving material to make the shearing operation. This 
type of shear is disadvantageous in that although the blades are 
vertically moved to provide a longer blade life than in the drum type 
flying shear there is required a relatively large number of arms forming 
the links and the installation becomes large and heavy in order to 
maintain a sufficient strength. 
As a billet shearing device in a continuous casting installation, there has 
been known a so-called pendulum-type shear in which vertically movable 
cutting blades are provided within a frame oscillatingly mounted on a 
crank shaft to shear the billet between the blades, as described, for 
example, in Journal of the Iron and Steel Institute, November, 1955, page 
6. In this type of shear, when the material is moved at a very low speed, 
such as within the range of 0.1 m/min to 2.0 m/min, as a billet, there is 
no problem, because the shearing operation is made with the frame urged as 
a pendulum by the material bitten between the blades, but such shear is 
unsuitable as a shear incorporated in a rolling line of the hot rolling 
installation in which the speed of movement of the material is very high, 
such as 10 m/min to 200 m/min, and the range of the speed to be selectable 
is large. Thus, the conventional pendulum-type shear is disadvantageous in 
that no means are provided for synchronizing the speed of the frame with 
that of the material and the impact between the blades and the material is 
too large to break the blades or/and shear in case of the hot rolling 
installation in which the speed of the material is large. 
For the purpose of shearing a thin sheet, there has often been used a 
so-called oscillatortype flying shear in which the material is sheared by 
an upper cutting blade secured to an oscillating frame and a mating lower 
cutting blade movable upward and downward within the frame by an eccentric 
mechanism. However, this type of shear is also disadvantageous in that the 
center of gravity of the frame is positioned above the center of 
oscillation, so that the gravity due to the weight of the oscillating 
portion, in addition to the varying power, is applied thereto, and if the 
capacity of the shear increases the weight of the oscillating portion will 
accordingly become increased to provide a construction resisting the 
reaction force. Therefore, it is unsuitable for shearing a thick sheet. 
The following are prior publications showing the background of the present 
invention. 
PRIOR PUBLICATIONS 
(1) Published Japanese Patent No. 41-16477 
(2) Published Japanese Patent No. 48-11554 
(3) Published Japanese Patent No. 44-18039 
(4) Iron and Steelworks Engineering (Journal of the Iron and Steel 
Institute, November, 1955, pages 239-240) 
(5) DEMAG W84.3 Pendulum Shear 
SUMMARY OF THE INVENTION 
The object of the present invention is to provide a pendulum-type flying 
shear suitable for a hot rolling installation in which the above-mentioned 
disadvantages of the prior arts are removed and the speed range is wide 
from a low speed to a high speed and a large cross-section of the material 
to be sheared can accurately be sheared with a small power and the 
construction is small in comparison with the conventional shear. 
According to the present invention, there is provided a pendulum-type 
flying shear comprising a main crank shaft rotated by driving means, a 
frame rotatably mounted on a first eccentric portion of said main crank 
shaft, a lower cutting blade fixed to said frame, an upper cutting blade 
rotatably mounted on a second eccentric portion of said main crank shaft, 
to move reciprocately within said frame and oscillating means for causing 
an oscillating movement of said frame about the first eccentric portion of 
said main crank shaft, in which said main crank shaft is rotated at a 
constant speed irrespective of the speed of movement of a material to be 
sheared and said oscillating means causes the oscillating movement of said 
frame in synchronous relationship with the speed of movement of the 
material whereby said driving means and said oscillating means start to 
operate in co-operation with a shearing instruction, and shears the 
material moving between said upper and lower cutting blades.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 diagrammatically shows an overall construction of pendulum-type 
flying shear in accordance with one embodiment of the present invention. A 
main portion 30 of the shear is driven through a reduction gear 20 by a 
direct-current electric motor 10 maintained at a constant speed. The 
rotating force derived from the motor 10 while reduced by the reduction 
gear 20 to an intended speed is transmitted to a driving- or 
operating-side frame 31 through a main crank shaft 33. The frame 31 is 
rotatably mounted on an eccentric portion of the main crank shaft 33. 
Provided between the frames 31 is another eccentric portion of the main 
crank shaft on which a connecting rod 34 is rotatably mounted as is in the 
case of the frames 31. A lower portion of the connecting rod 34 is 
connected with an upper cutting blade table 35 for fixing an upper cutting 
blade 36, the table being adapted to slidably move within the frames in 
the vertical direction. The lower portions of the frames 31 are provided 
with a lower cutting blade table 37 for fixing a lower cutting blade 38. 
Another axis of the reduction gear transmits a rotating force for driving 
an eccentric crank 41 through a speed synchronizing mechanism (not shown 
in FIG. 1). This rotating force of the eccentric crank is transmitted to 
the frames 31 through an arm 42, an angular movable arm 43, a torque 
transmitting shaft 44, an angular movable arm 47 and a rod 46 to cause 
oscillating movements of the frames 31 about the eccentric portion of the 
crank shaft 33 in the direction of the arrow 2. Such oscillating movements 
are in synchronous relationship with the speed of movement of a material 1 
to be sheared, and the oscillating mechanism will be described 
hereinlater. 
The main portion 30 of the shear will next be described by reference to 
FIGS. 2 to 5. The rotating force transmitted from the reduction gear 20 
through a coupling 336 is transmitted as a rotating force for the main 
crank shaft 33 rotatably supported by bearings 334, 335 mounted on bases 
51, 52. The main crank shaft 33 is provided with eccentric portions having 
predetermined phase angles, and the frames 31 integrally formed with each 
other are mounted for oscillating movements on first eccentric portions 
331 and 332 having an eccentric radius R.sub.2. The connecting rod 34 for 
moving the upper cutting blade 36 in the vertical direction is rotatably 
mounted on second eccentric portion having an eccentric radius R.sub.3. 
Provided on left and right sides of the upper and lower cutting blade 
tables 35 and 37 are upper cutting blade balancing cylinder 39 and lower 
cutting blade urging cylinder 32 having pistons and rods for varying the 
gap between the upper and lower cutting blades 36 and 38, such that the 
gap can be increased by operating the cylinders. In this condition, the 
lower cutting blade table 37 together with the upper cutting blade table 
35 are pulled out from a window portion of the frame by cutting blade 
replacing means disposed perpendicular to a line not shown. Thus, there 
will be no need to make the replacement of the cutting blades under bad 
conditions of the location or environment in the line. 
As shown in FIG. 3, an end of the connecting rod 34 is connected with a 
V-shaped connecting block 341 which is, in turn, connected with a 
reinforcing block 342 through a connecting key 345. The reinforcing block 
342 comprises a pair of centrally divided halves fixed by a tension bolt 
344 to each other to form a V-shaped cavity engaged with the connecting 
block 341. The tension bolt 344 is formed at its mid portion with a 
constriction which is broken out when a determined overload is applied 
thereto, and serves as a safety device for interrupting the transmission 
of the load to the driving mechanism, when the material to be sheared has 
a lower temperature than the determined value or when an excess load is 
applied to the upper cutting blade 36 by virtue of the plate to be sheared 
having a larger thickness or width than the determined value. 
As shown in detail in FIG. 4, furthermore, provided between the upper 
cutting blade table 35 and the frame 31 are springs 345 for urging the 
table 35 against the other frame 31 during the shearing operation, thereby 
maintaining the table 35 in a fixed position. When it is desired to 
replace the upper cutting blade 36 with new one, a keep plate 346 inserted 
for releasing the springs 345 is urged by a releasing cylinder 347 to 
release the springs 345. 
In respect of the lower cutting blade table 37, similarly as shown in 
detail in FIG. 5, an urging cylinder 348 is provided between the table 37 
and the frame 31 to urge the table 37 against the frame 31 in the same 
direction as the side pressure applied to the table 37 during the shearing 
operation. 
On the opposite side of the lower cutting blade table, there is provided a 
wedge 349 between it and the frame 31 to make an adjustment of the gap 
between the upper and lower cutting blades 36 and 38. 
In this manner, with this embodiment, even when the frames 31 are 
oscillated the upper cutting blade table is not moved laterally relative 
to the frame 31, and the gap between the upper and lower cutting blades 
can easily be adjusted. 
The arrangment of the device for causing the oscillating movements of the 
frames 31 in synchronous relationship with the speed of movement of the 
material will next be described by reference to FIG. 6. One end of torque 
transmitting shafts 44 connected by a coupling 48 to each other is 
connected to the eccentric crank 41 through the angularly movable arm 43 
and the rod 42. A shaft end of the speed synchronizing mechanism including 
planetary gear mechanism and differential gear mechanism to be described 
hereinafter is connected to the eccentric crank 41 and two other shaft 
ends are connected through a coupling 49 and clutch 45, respectively, to 
the reduction gear 20. 
The clutch 45 is provided in such a manner that when an excess load is 
applied to the cutting blades no excess load is transmitted to the 
reduction gear 20 and the driving motor 10. 
In order to cause the oscillating movements of the frames 31 in synchronous 
relationship with the speed of movement of the material, the reduction 
gear 20 driven by the motor 10, and the speed synchronizing oscillating 
mechanism including the eccentric crank 41, the rod 42, the angularly 
movable arm 43, the torque transmitting shaft 44, the angularly movable 
arm 47 and the rod 46 are disposed adjacent to the driving side of the 
main portion of the shear, i.e. on the side perpendicular to the flow of 
the material and on which the motor 10 is disposed. This results in the 
facts that the driving side has a sufficient space to make the replacement 
of the blades and that there can be provided a speed synchronizing device 
having a high strength without obstructing the operator's view on the 
operating side, because of the provision of a large size of the speed 
synchronizing device corresponding to the increased capacity of the shear. 
There is a further effect that the construction of the upper portions of 
the frames is simple so that a ceiling crane can effectively be used when 
maintaining or inspecting the shear. 
The mechanism for causing the oscillating movements synchronous with the 
material feeding speed will next be described by reference to FIG. 7. The 
eccentric crank 41 is connected to one shaft end of the speed 
synchronizing device 40, that is to a pinion 411 for eccentricity of 
planetary gear mechanism 410. The pinion 411 is in tooth-to-tooth 
engagement with an internal gear 412 for eccentricity which is driven 
through a clutch 45, a gear 415 and a gear 416. Furthermore, a support 
417, which supports the center axis of a pinion 411, is rotated by a 
rotating force transmitted from the driving device through differential 
gears 420 to gears 413, 414. 
In order to vary the rotating radius R.sub.1 of the eccentric crank 41, a 
worm 422 of differential gear device 421 of the differential gear 
mechanism 420 is rotated by a motor 423 to rotate the pinion 411 relative 
to the internal gear 412. By this relative rotation of the pinion 411, the 
eccentric radius R.sub.1 of the crank 41 is varied. When the eccentric 
radius R.sub.1 is set to a desired value, the rotation of the motor 423 is 
ceased and the frames 31 will cause oscillating movements at a desired 
speed. 
FIGS. 8 and 9 show a condition in which the eccentric radius R.sub.1 of the 
eccentric crank 41 is varied to R.sub.1 ' by the planetary gear mechanism 
410 with the differential gear mechanism 420 rotated. When the eccentric 
crank 41 is set to have the desired eccentric radius R.sub.1 and the 
oscillating movement of the frames 31 is caused, the upper and lower 
cutting blades 36 and 38 fixed to the frames 31 are moved to draw foci 81 
and 82, respectively. In this condition, the shearing operation is 
initiated when the lower cutting blade 38 is at a position P. When the 
eccentric radius R.sub.1 is varied to R.sub.1 ' in accordance with the 
speed of movement of the material to be sheared, the amplitude of the 
oscillating movement of the frames 31 is varied such that the upper and 
lower cutting blades 36 and 38 are moved to draw different foci 83 and 84, 
respectively, and the point at which the shearing operation is initiated 
is shifted to a point Q. Accordingly, the point at which the shearing 
operation is initiated is shifted, when the speed of oscillating movement 
of the frames is synchronized with the speed of movement of the material. 
FIG. 7 will again be referred to in order to explain control means for 
making a precise shearing operation at a desired position, even when such 
point is shifted. 
The angular position of the main crank shaft 33 is detected by a detector 
61 for detecting the absolute position of the main crank. The angular 
position of the planetary gear mechanism 410 is also detected by a 
detector 62 for detecting the absolute position of the planetary gear. 
Furthermore, the speed of feeding the material 1 to be sheared is detected 
by a speed meter 64 of a measuring roller 63. The position of the material 
is detected through a pulse generator 65 of the measuring roller 63 and a 
pulse counter 66. The operation of the pulse counter 66 is controlled by a 
metal detector 67. These detected signals of the angular position of the 
main crank, the angular position of the planetary gear, the speed of 
feeding the material and the position of the material are supplied to 
operational device 68 the output of which is supplied as a control signal 
through a speed controller 69 into a speed control device 70 in which it 
is compared with the output of a speed meter 71 of the motor 10 to control 
the start of the motor 10 and the acceleration and reduction patterns 
thereof. 
In this manner, with the present embodiment the position of the upper and 
lower cutting blades at which the shearing operation is initiated is 
precisely detected by detecting the angular positions of the main crank 
shaft and the planetary gear, and in accordance with these detected values 
the precise shearing operation can be made at the desired shearing 
position with the speed of oscillating movement of the cutting blades 
synchronized with the speed of feeding the material. 
In the embodiment described above, the oscillating movement of the frames 
31 and the angular movement of the main crank shaft are made by the single 
motor 10 and the synchronization of the oscillating movement of the frames 
31 with the speed of feeding the material to be sheared is made by varying 
the eccentric radius of the eccentric crank for connecting the main crank 
shaft driving motor and the frame oscillating device. With the present 
invention, however, it is possible to use a speed synchronizing motor for 
synchronizing the frame oscillating speed with the material feeding speed, 
in addition to the main crank shaft driving motor. It is further possible 
to automatically control both of these motors in accordance with the 
material speed and the size of the area to be sheared, such that the 
opening and speed of the blades at the initiation of shearing are set to 
optimum values. 
FIG. 10 shows another embodiment of the present invention provided with 
such a speed synchronizing motor. The same reference numerals as in FIG. 1 
designate the same parts and no description thereto will be given 
hereinbelow. 
The frames 31 are connected with the rod 46 for causing the oscillating 
movement of the frames in the direction of movement of the material 1 to 
be sheared, the rod 46 being connected to the arm 47 supported by the 
torque transmitting shaft 44. Secured to the shaft 44 is a further arm 43 
which is connected to the rod 42. This rod 42 is coupled to a speed 
synchronizing crank 432 having a constant eccentric radius and rotated by 
the speed synchronizing motor 431 through a fly-wheel 433 and a worm 
reduction device 430. 
With this, the horizontal speed of the cutting blades when shearing 
operation, and thus the oscillating speed of the frames are controlled in 
synchronous with the speed of feeding the material to be sheared. FIG. 11 
shows such a control mechanism and the same reference numerals as in FIGS. 
7 and 10 designate the same parts. 
The speed of the material 1 is detected by the measuring roller 63 and the 
speed meter 64 and these detected values are transmitted to the pulse 
generator 65, the operational device 68 and the speed controller 435, 
respectively. The output of the pulse generator 65 is further transmitted 
to the pulse counter 66. The position of the material 1 is detected by the 
metal detector 67 and this detected value is transmitted to the pulse 
counter 66. The output of the pulse counter 66 is delivered to said 
operational device 68 as a signal of the shearing position of the material 
1. The operational device 68 transmits the start instructions in 
accordance with the thickness and speed of the material to the speed 
controllers 436 and 69. 
The output of the speed controller 69 is transmitted to the main crank 
driving motor 10 through the speed control device 70 which makes the 
starting and stopping operations at the determined speed while detecting 
the rotating speed of the motor 10 by the speed meter 71. 
The speed synchronizing motor 431, while its rotational speed is detected 
by the speed meter 434, is controlled by the instructions of the speed 
synchronizing device 435 in accordance with the instructions of the speed 
controller 436 so that the oscillating movement of the frames 31 is 
started and stopped in synchronous with the speed of the material. 
The angular positions of the main crank shaft 33 and the speed 
synchronizing crank 432 are detected by potentiometers 61 and 437, 
respectively. The phases of the detected values of the potentiometers 61 
and 437 are compared with each other by the operational devices 68 and 438 
and a control is made to synchronize these phases with the intended values 
thereby adjusting the speed of the motor 431. 
In the above embodiment the worm reduction device 430 and the fly-wheel 433 
are interposed between the speed synchronizing crank 432 and the speed 
synchronizing motor 431, such that the inertia force resulting from the 
oscillating movement of the frames 31 cannot be directly transmitted to 
the speed synchronizing motor 431 and thus the motor 431 may be of a 
minimum allowable strength and capacity. In case of the material being 
relatively small, furthermore, the worm reduction device 430 may be 
replaced by a different type of the reduction device only provided with 
the fly-wheel 433 thereby lowering the reaction torque applied to the 
motor 431. 
In this manner, with this embodiment the main crank driving motor and the 
speed synchronizing motor are mutually automatically controlled to set the 
opening and speed of the cutting blades to the optimum values when 
initiating the shearing operation and thus there are advantages that the 
construction is simple and the speed of the material can widely be varied 
from the high speed region to the low speed region, and the material 
having a large shearing cross-section can precisely be sheared by a small 
power. 
The examples have hereinabove been described in which as the driving motor 
10 a direct current electric motor easily making the speed control is 
rotated at a rated rotating speed and the fine adjustment of the rotating 
speed is made by ASR to control the shearing position and the speed 
synchronization is made by maintaining the driving motor at a constant 
speed and varying the radius of the eccentric crank, or by using the speed 
controllable speed synchronizing electric motor 431 only for causing the 
oscillating movements. This results in the fact that the driving motor 10 
requiring the large capacity is rotated at a substantially constant speed 
so as to be always driven at its maximum efficiency and thus the capacity 
of the driving motor can largely be reduced in comparison with the 
conventional equipments. With an example of the present invention, the 
motor capacity can be reduced by about 1/4.3 in comparison with a 
conventional four-link type flying shear and the machine weight can also 
be reduced by 1/1.5. In case of a shear permitted to have a relatively 
rough shearing accuracy, however, it is possible that the motor 10 is 
arranged by an alternating current electric motor suitable for constant 
rotation, and in this case there is no need to provide the motor and 
control system therefor and thus the cost can largely be reduced. 
As described above, according to the present invention the precise shearing 
of a large cross-section of the material to be sheared can be achieved at 
a speed ranging from the low speed to the high speed, and the driving 
motor is driven at the substantially rated speed so that the motor may be 
of a small size and small power to largely reduce the power consumption 
required for the shearing operation. Furthermore, according to the present 
invention the center of gravity of the frames is positioned below the 
center of the oscillating movement so that the gravity of the weight of 
the oscillating portion acts to diminish the varying power. Therefore, 
there is an effect that as a large capacity is required a small and light 
weight construction can be used.