Clamping and cutting apparatus

Clamping and cutting apparatus to be incorporated with a heading machine comprises a carriage having a shearing cutter mounted thereon and movable between a cutting position where rod-shaped work is cut to a predetermined length and a transfer position where the cut piece of work is transferred to the subsequent processing station. A clamp lever mounted on the carriage is connected via a toggle joint to a slider also mounted thereon, which slider is slidable either to a positive clamping position for causing the clamp lever to positively clamp the work against the cutter, a loose clamping position for causing the clamp lever to loosely clamp the work, or an unclamping position for causing the clamp lever to release the work. When the carriage is in the cutting position, the slider can be locked in the positive clamping position by a pivotal locking pawl via blocks of elastomeric material, and as the carriage travels to the transfer position upon completion of each cutting operation, the locking pawl is cam operated to permit the slider to be moved to the loose clamping position and thence to the unclamping position.

BACKGROUND OF THE INVENTION 
This invention relates to clamping and cutting apparatus, and more 
specifically to such apparatus of the type to be incorporated with a 
header or heading machine used for producing the heads of bolts, rivet, 
screws and like fasteners. 
In clamping and cutting apparatus of the type under consideration, the 
positive clamping of work is a prerequisite for cutting it to the precise 
length or size required and for improving the dimensional accuracy of the 
end products. Further, when the apparatus is incorporated with a header or 
the like, it should be so constructed as to allow ready transfer of each 
severed piece of work to the subsequent processing station. 
The clamping and cutting apparatus incorporated with a header has another 
serious problem arising when work, which is rod shaped, is cut to less 
than a predetermined length. If such an undersized piece of work is 
allowed to be transferred to the subsequent processing station such as the 
first forming station, troubles may take place such as the seizure of the 
forming die sections and the damage of transfer fingers. 
SUMMARY OF THE INVENTION 
It is an object of this invention to provide clamping and cutting apparatus 
capable of clamping work so positively that it can be cut to a precise 
size desired. 
Another boject of the invention is to provide clamping and cutting 
apparatus well adapted for combined use with a header or the like, the 
apparatus being capable of transporting each severed piece of work to the 
subsequent processing station such as the first forming station of the 
header. 
A further object of the invention is to provide clamping and cutting 
apparatus so constructed that each severed piece of work can be held 
positively clamped during transportation to the subsequent processing 
station. 
A still further object of the invention is to provide clamping and cutting 
apparatus so constructed that in event work is cut to less than a 
predetermined size, the undersized piece of work can be automatically 
withdrawn from the apparatus before it reaches the subsequent processing 
station. 
In accordance with this invention, briefly summarized, there is provided 
clamping and cutting apparatus comprising a carriage having cutter means 
thereon and movable between a cutting position where work is cut to a 
predetermined size and a transfer position where the cut piece of work is 
transferred to the subsequent processing station. A clamp lever pivotally 
mounted on the carriage is operatively connected to a slider supported by 
support means fixedly mounted on the carriage, with the slider being 
movable relative to the carriage between a clamping position for causing 
the clamp lever to clamp the work against the cutter means on the carriage 
and an unclamping position for causing the clamp lever to release the 
work. The slider is yieldably urged to move from the clamping to 
unclamping position by actuator means such as, for instance, a 
single-acting air cylinder having constant supply of pressurized air into 
its working chamber. A locking member is pivotally mounted on the support 
means for movement between a locking position for locking the slider in 
the clamping position and an unlocking position for permitting the slider 
to be moved from the clamping to unclamping position by the actuator 
means, with the locking member being spring biased to move from the 
unlocking to locking position. 
The apparatus further comprises resilient means, preferably in the form of 
one or more blocks of elastomeric material, which is adapted to be 
compressed when the slider is locked in the clamping position, with the 
result that by virtue of the reactive force of the resilient means, the 
slider is urged to move further in such a direction that the clamp lever 
clamps the work more positively. 
When the carriage is in the cutting position, the slider is moved to the 
clamping position by reciprocating means mounted on frame means of the 
apparatus and is locked in that position by the locking member. After the 
carriage has travelled from the cutting to transfer position upon 
completion of each cutting operation, cam means carried by the 
reciprocating means operates to cause the locking member to unlock the 
slider and hence to permit same to be moved from the clamping to 
unclamping position by the actuator means. 
Thus, work to be cut can be positively clamped when the carriage is in the 
cutting position, and upon completion of the subsequent cutting operation, 
the cut piece of work can be transported to the next processing station by 
the carriage while being held positively clamped thereon. Further, the 
piece of work is unclamped automatically when the carriage reaches the 
transfer position. 
According to a further feature of this invention, the locking member is 
capable of locking the slider in a loose clamping position, in addition to 
the aforementioned clamping position which is hereinafter termed the 
positive clamping position. When the slider is locked in the loose 
clamping position, the work is relatively loosely clamped by the clamp 
lever because then the resilient means such as blocks of elastomeric 
material is less compressed than when the slider is locked in the positive 
clamping position. After the carriage has travelled to the transfer 
position upon completion of each cutting operation, the locking member is 
operated by the cam means to permit the slider to be moved from the 
positive to loose clamping position and thence to the unclamping position, 
so that each cut piece of work is temporarily held loosely clamped in the 
transfer position before being finally unclamped. 
According to a still further feature of this invention, second cam means is 
retractably mounted on the frame means and is adapted to be moved to its 
working position only when work is cut to less than a predetermined size. 
The second cam means when in its working position is effective to cause 
the locking member to unlock the slider immediately when or after the 
carriage starts travelling from the cutting toward transfer position. The 
undersized piece of work can therefore be unclamped for immediate 
withdrawal before the carriage reaches the transfer position. 
The above and other objects, features and advantages of this invention and 
the manner of attaining them will become more apparent, and the invention 
itself will best be understood, upon consideration of the following 
description with reference had to the accompanying drawings showing a 
preferred embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIGS. 1 and 2 best illustrate a preferred form of the clamping and cutting 
apparatus according to this invention which can be incorporated with a 
header of prior art design. Broadly, the clamping and cutting apparatus 
comprises frame means including a platform 10, a carriage 12 reciprocally 
movable horizontally relative to the frame means, a clamp lever 14 
pivotally mounted on the carriage for clamping rod-shaped work W against a 
shearing cutting 16 mounted on the carriage, a slider 18 in the form of a 
rod slidably supported by a support 20 fixedly mounted on the carriage and 
connected at one end to the clamp lever via a toggle joint 22, actuator 
means such as a single-acting air cylinder 24 connected to the other end 
of the slider 18 and tending to move same leftwardly, as seen in FIGS. 1 
and 2, relative to the support 20, a locking pawl 26 pivotally mounted on 
the support for locking the slider 18 in such a position that the work W 
is clamped by the clamp lever 14 either positively or loosely, resilient 
means 28 adapted to be compressed when the slider 18 is locked by the 
locking pawl 26, reciprocating means 30 mounted on the platform 10 for 
movement toward and away from the support 20, and an elongate cam plate 32 
carried by the reciprocating means 30 for actuating the locking pawl 26 
via a cam follower pin 34 affixed thereto. 
The carriage 12 is slidable along a slideway 36 under the platform 10 
between a cutting position shown in FIGS. 1, 4 and 5, where the work W is 
cut to a predetermined length, and a transfer position shown in FIGS. 6 
and 7, where the cut piece of work is transferred to the subsequent 
processing station such as the first forming station. The shearing cutter 
16 is bolted or otherwise fastened to the carriage 12. 
Pivotally pinned at 38 to the carriage 12, the clamp lever 14 has a 
clamping surface 40 of steel or like material to be pressed directly 
against the work W on the cutter 16. The free end of this clamp lever is 
operatively connected to the slider 18 via the toggle joint 22 and, 
preferably, a turnbuckle 42. The toggle joint 22 comprises a bell crank 44 
fulcrumed at 46 on the carriage 12, and a link 48 pivotally connecting one 
of the arms of the bell crank to the clamp lever 14. The other arm of the 
bell crank 44 is pivotally connected to the turnbuckle 42 and thence to 
the slider 18. 
The slider 18, slidably supported by the support 20, has its left hand end 
projecting outwardly therefrom, and on this projecting end of the slider 
there are mounted a pair of parallel spaced plate members 50 and 52 with 
the resilient means 28 sandwiched therebetween. The right hand plate 
member 50 is secured to the slider 18, but the left hand plate member 52 
is slidably mounted thereon for movement toward and away from the right 
hand plate member within limits. Preferably, the resilient means 28 takes 
the form of one or more, two in the illustrated embodiment, blocks of 
elastomeric material such as polyurethane rubber. 
As best seen in FIG. 1, the right hand plate member 50 has an upward 
extension 54, to which there is connected the piston rod 56 of the 
single-acting air cylinder 24 mounted on the support 20. This air cylinder 
has constant supply of pressurized air into its head end chamber from a 
suitable source of such pressurized air, not shown, so that the slider 18 
is under constant pressure to move leftwardly relative to the support 20. 
The locking pawl 26 is pivotally pinned at 58 to the support 20 and is 
biased to turn clockwise, as seen in FIG. 1, by a helical extension spring 
60. The locking pawl 26 can be turned to either of first and second 
locking positions and an unlocking position by means hereinafter set 
forth. 
In the first locking position the locking pawl 26 has its first step 62 in 
engagement with the left hand plate member 52 on the slider 18, as shown 
in FIGS. 1, 5 and 6, with the result that the slider is locked in a 
positive clamping position to cause the clamp lever 14 to clamp the work W 
via the turnbuckle 42 and the toggle joint 22. With the slider 18 thus 
locked in the positive clamping position, the blocks of elastomeric 
material 28 become compressed between the pair of plate members 50 and 52 
to such an extent that a high reactive force is applied to the slider in 
such a direction as to add to the clamping force of the clamp lever 14. 
The work W can therefore be positively clamped against any possibility of 
dislodgement. 
In the second locking position the locking pawl 26 has its second step 64 
in engagement with the left hand plate member 52, with the result that the 
slider 18 is locked in a loose clamping position to cause the clamp lever 
14 to clamp the work W relatively loosely. This is because the blocks of 
elastomeric material 28 are then significantly less compressed than when 
the slider 18 is locked in the positive clamping position. 
In the unlocking position the locking pawl 26 is out of engagement with the 
left hand plate member 52 as shown in FIGS. 4 and 7. The slider 18 is 
therefore free to be moved leftwardly to an unclamping position, also as 
shown in FIGS. 4 and 7, by the air cylinder 24 relative to the support 20. 
The work W is then released by the clamp lever 14. 
The reciprocating means 30 comprises a yoke 66 slidable along a guide rod 
68 extending between upstanding support members 70 and 72 mounted on the 
platform 10. The yoke 66 is pivotally connected to a turnbuckle 74 and 
thence to one of the arms of a bell crank 76 which is fulcrumed at 78 on a 
stationary enclosure, not shown, of the carriage 12. The other arm of the 
bell crank 76 is pivotally connected to a rod 80 which is moved up and 
down by, for instance, a cam mechanism associated with the drive 
mechanism, not shown, of the carriage 12. 
Also included in the reciprocating means 30 are first and second 
reciprocating rods 82 and 84 which are both rigidly connected to the yoke 
66 and which slidably extend through a guide block 86 on the platform 10 
in parallel spaced relationship. The first reciprocating rod 82 has a 
leftward extension 88 slidably extending through a guide hole 90 formed in 
the support member 70. The right hand end of this first reciprocating rod 
is disposed opposite to the left hand plate member 52 for movement into 
and out of abutting contact therewith. 
Thus, with the up-and-down motion of the rod 80, the yoke 66 together with 
the first and second rods 82 and 84 is reciprocated between a right hand 
position indicated by the solid lines in FIG. 1 and a left hand position 
indicated by the dot-and-dash lines in the same drawing. Upon movement of 
the yoke 66 to the right hand position while the carriage 12 is in the 
cutting position, the slider 18 is moved to the positive clamping position 
by the first reciprocating rod 82 against the forces of the air cylinder 
24 and blocks of elastomeric material 28 and is locked in that position by 
the locking pawl 26, as shown in FIG. 5. 
Affixed to the second rod 84 of the reciprocating means 30, the elongate 
cam plate 32 has first and second sloping edges or surfaces 92 and 94 for 
sliding contact with the cam follower pin 34 extending laterally from the 
free end of the locking pawl 26. During the leftward stroke of the yoke 66 
while the carriage 12 is in the transfer position of FIG. 6, the locking 
pawl 26 is turned from its first to second locking position against the 
force of the extension spring 60 as the cam follower pin 34 relatively 
slides down the first cam edge 92, so that the slider 18 is moved from its 
positive to loose clamping position. Subsequently, as the cam follower pin 
34 relatively slides down the second cam edge 94 upon completion of the 
leftward stroke of the yoke 66, the locking pawl 26 is turned from its 
second locking to unlocking position against the force of the extension 
spring 60. Thereupon the slider 18 is moved from its loose clamping to 
unclamping position by the air cylinder 24, so that the clamp lever 14 
releases the work W as shown in FIG. 7. 
As illustrated in FIGS. 2 and 3, another cam 96 is pivotally mounted on the 
platform 10 for 90.degree. angular displacement between operative and 
inoperative positions. In the operative position the cam 96 has its 
sloping surface 98 disposed opposite to the cam follower pin 34 for 
turning the locking pawl 26 from its first locking to unlocking position 
against the force of the extension spring 60 immediately when or after the 
carriage 12 starts travelling from the cutting toward transfer position. 
In the inoperative position the cam 96 permits unobstructed passage 
therepast of the cam follower pin 34 during the travel of the carriage 12 
between the cutting and transfer positions. The cam 96 is operatively 
connected to the piston rod 100 of a fluid actuated cylinder 102, 
preferably an air cylinder, so as to be thereby moved between its 
operative and inoperative positions. 
Normally, the cam 96 is held in its inoperative position and is turned to 
its operative position by the air cylinder 102 only when the work W is cut 
to less than a predetermined length. Such an undersized piece of work is 
detected by means comprising a proximity switch associated with a rotary 
cam mechanism, both not shown, and a solenoid valve or the like, also not 
shown, is thereby actuated for delivering pressurized air into the head 
end chamber of the air cylinder 102 and hence for turning the cam 96 from 
its inoperative to operative position. 
OPERATION 
While the operation of the clamping and cutting apparatus according to this 
invention is believed clearly apparent from the foregoing description, 
further amplification will be made in the following brief summary of such 
operation, with reference had principally to FIGS. 4 through 7. 
In FIG. 4 the carriage 12 is shown in the cutting position, and the yoke 66 
together with the first and second reciprocating rods 82 and 84 in the 
left hand position. The left hand plate member 52 is now unlocked from the 
locking pawl 26, so that the slider 18 is moved to and held in the 
unclamping position by the air cylinder 24 via the right hand plate member 
50. The clamp lever 14 is therefore pivoted away from the cutter 16 via 
the turnbuckle 42 and the toggle joint 22. 
While the apparatus is in the condition of FIG. 4, the rod-shaped work W is 
fed a predetermined distance and placed in position on the cutter 16. Then 
the rod 80 of FIG. 1 is lowered to move the yoke 66 to the right hand 
position via the bell crank 76 and the turnbuckle 74, as shown in FIG. 5. 
As the first reciprocating rod 82 connected to the yoke 66 is thus moved 
rightwardly, the slider 18 is thereby moved in the same direction via the 
left hand plate member 52, blocks of elastomeric material 28 and right 
hand plate member 50 against the force of the air cylinder 24, until the 
left hand plate member becomes engaged by the first step 62 of the locking 
pawl 26 with the blocks of elastomeric material compressed to the maximum 
between the pair of plate members 50 and 52. With the slider 18 thus 
locked in the positive clamping position, the work W is positively clamped 
by the clamp lever 14 against the cutter 16. It should be appreciated that 
the compressed blocks of elastomeric material 28 coact with the toggle 
joint 22 to enable the positive clamping of the work W by the clamp lever 
14. 
The work W is then cut to a predetermined length, and the cut piece of work 
is held positively clamped by the clamp lever 14. The method of cutting 
the work is conventional, so that its description is omitted. 
Upon completion of the cutting operation, the carriage 12 together with the 
clamp lever 14, support 20 and other means mounted thereon is moved from 
the cutting to transfer position, while the yoke 66 together with the 
first and second reciprocating rods 82 and 84 is left in the right hand 
position, as shown in FIG. 6. It will be apparent from the drawing that 
the cut piece of work W is held positively clamped throughout the course 
of travel of the carriage 12 from the cutting to transfer position. 
When the carriage 12 reaches the transfer position with the positively 
clamped piece of work W, the rod 80 of FIG. 1 is raised by the unshown cam 
mechanism to move the yoke 66 from the right to left hand position. As the 
cam plate 32 carried by the second reciprocating rod 84 travels leftwardly 
with the yoke 66, its first sloping edge 92 slides over the cam follower 
pin 34 to turn the locking pawl 26 counterclockwise from its first to 
second locking position against the force of the extension spring 60. As a 
consequence, the slider 18 moves leftwardly a slight distance from its 
positive to loose clamping position, and the blocks of elastomeric 
material 28 become less compressed than when the slider is locked in the 
positive clamping position. The piece of work W is now only loosely 
clamped by the clamp lever 14. 
At the end of the leftward stroke of the yoke 66, the second sloping edge 
94 of the cam plate 32 slides over the cam follower pin 34 to turn the 
locking pawl 26 further counterclockwise from its second locking to 
unlocking position against the force of the extension spring 60. Then, as 
illustrated in FIG. 7, the slider 18 is moved further leftwardly from its 
loose clamping to unclamping position by the air cylinder 24, with the 
blocks of elastomeric material 28 recovering their original shape. The 
clamp lever 14 is therefore pivoted counterclockwise to release the piece 
of work W, which may then be fed into the die of the first forming station 
of the header by suitable means. Thereafter the foregoing cycle of 
clamping, cutting and transferring operations is repeated. 
In event the work W is cut to less than a predetermined length, the 
aforesaid detecting means actuates the unshown solenoid valve to deliver 
pressurized air into the head end chamber of the air cylinder 102. The 
piston rod 100 of this air cylinder is then extended to cause the 90 
degrees angular motion of the cam 96 from its inoperative to operative 
position, as depicted in FIG. 2. The sloping surface 98 of the cam 96 is 
now disposed opposite to the cam follower pin 34 on the locking pawl 26. 
Thus, immediately when or after the carriage 12 subsequently starts 
travelling from the cutting toward transfer position, the cam follower pin 
34 becomes engaged by the cam 96 and slides down its sloping surface 98. 
The locking pawl 26 is therefore turned counterclockwise from its first 
locking to unlocking position past the second locking position against the 
force of the extension spring 60. Since then the slider 18 is moved 
leftwardly from its positive clamping to unclamping position past the 
loose clamping position by the air cylinder 24, the clamp lever 14 is 
turned counterclockwise to release the undersized piece of work. 
The undersized piece of work, released by the clamp lever 14, is to be 
withdrawn from the cutter 16 before the carriage 12 reaches the transfer 
position. This objective can be accomplished by use of, for example, a 
forced flow of air for blowing away the undersized piece of work from the 
cutter 16. The means for producing such a flow of air is not illustrated 
because it is considered easy for the specialits to devise such means. 
While the clamping and cutting apparatus in accordance with this invention 
has been shown and described in terms of its specific form, it is 
understood that the invention itself is not to be restricted by the exact 
details of this disclosure. Numerous modifications or changes will readily 
occur to those skilled in the art without departing from the spirit or 
scope of the invention as sought to be defined by the following claims.