Cutting press with stroke terminating means

In a cutting press of the type wherein an upper platen is forced toward a lower platen to press a die through a workpiece on the lower platen, a more easily operable stroke setting means is provided. In the course of low pressure actuation of the upper platen for this purpose, an operator need only deactivate a solenoid whereby a brake becomes effective to establish the cutting stroke as appropriate to the depth of a die, for subsequent high pressure cutting strokes of the press.

BACKGROUND OF THE INVENTION 
This invention is concerned with improvements in or relating to cutting 
presses. 
Cutting presses which comprise an upper platen, a lower platen, and 
hydraulic piston and cylinder means for moving the upper platen so that 
the upper platen approaches the lower platen whereby to effect a cutting 
stroke of the press are well known. An example of such a press is 
described, for instance, in British patent specification No. 1,035,816. In 
the operation of such a press, a workpiece is placed on the lower platen 
and a shaped knife or die is placed on top of the workpiece. The hydraulic 
piston and cylinder means is then operated so that the upper platen 
presses the knife or die through the workpiece. The upper platen may be 
supported above the lower platen on one, two or four columns. 
A cutting press is described in British patent specification No. 1,342,585 
published Jan. 3, 1974, which comprises an upper platen supported on one 
column above a lower platen thereof, means for effecting relative movement 
of approach between the platens whereby to effect a cutting stroke of the 
press, and stroke control means. The stroke control means comprises stroke 
terminating means effective to terminate a cutting stroke of the press and 
stroke setting means for setting the distance of a cutting stroke 
according to the depth of the cutting die in use. The stroke terminating 
means comprises a switch and an actuator therefor which is moved as the 
platens move together, and the stroke setting means is arranged to 
position the switch at a stroke-terminating position. The stroke setting 
means comprises a carriage on which the switch is mounted and brake means 
for holding the carriage against movement on a slideway therefor. The 
brake means requires an operator to pull the brake means into an off 
position and maintain it there so that a stroke setting operation of the 
press may be made to position the switch. In some circumstances, this form 
of brake means is difficult to operate. 
SUMMARY OF THE INVENTION 
It accordingly is an object of the present invention to provide an improved 
cutting press having stroke setting means which is more convenient to 
operate. 
There is hereinafter described a cutting press which is illustrative of the 
invention. The illustrative press comprises an upper platen, a lower 
platen, means for moving the upper platen so that the upper platen 
approaches the lower platen whereby to effect a cutting stroke of the 
press, stroke terminating means and, notably, improved stroke setting 
means. 
The stroke terminating means of the illustrative press comprises an 
actuator member which projects from a rod connected to the upper platen. 
Movement of the upper platen causes movement of the rod and thus the 
actuator member is moved in a vertical path. The stroke terminating means 
also comprises a microswitch mounted in the path of the actuator member to 
be operated thereby. Operation of the microswitch is effective to 
terminating a cutting stroke of the press. 
The stroke setting means of the illustrative press is for bringing the 
microswitch of the stroke terminating means to a stroke-terminating 
position. The stroke setting means comprises a carriage mounted for 
vertical movement on a slideway adjacent to the path of the actuator 
member. The microswitch of the stroke terminating means is mounted on the 
carriage. The stroke setting means also comprises brake means in the form 
of a lever which is movable between an operative condition in which it 
holds the carriage against movement on the slideway and an inoperative 
condition, and moving means in the form of a tension or clock spring which 
urges the carriage upwards on the slideway. 
The stroke setting means of the illustrative press also comprises an 
abutment member mounted on the carriage for movement between an operative 
position thereof in which it projects into the path of the actuator member 
and an inoperative position thereof, and operating means in the form of a 
solenoid arranged, when energized, to move the brake means into its 
inoperative condition and the abutment member into its operative position. 
The present invention provides a cutting press comprising an upper platen, 
a lower platen, means for moving the upper platen so that the upper platen 
approaches the lower platen whereby to effect a cutting stroke of the 
press, stroke terminating means comprising an actuator member mounted for 
movement in a vertical path and interconnected with the upper platen so 
that movement of the upper platen brings about corresponding movement of 
the actuator member, and a switch mounted in the path of the actuator to 
be operated thereby, operation of the switch being effective to terminate 
a cutting stroke of the press, and stroke setting means for bringing the 
switch of the stroke terminating means to a stroke-terminating position 
appropriate to a cutting die to be used for subsequent cutting operations, 
the stroke setting means comprising a carriage mounted for vertical 
movement on a slideway adjacent to the path of the actuator member, the 
switch of the stroke terminating means being mounted on the carriage, 
brake means movable between an operative condition in which it holds the 
carriage against movement on its slideway and an inoperative condition in 
which it allows the carriage to move on its slideway, moving means 
arranged to urge the carriage upwards on its slideway, an abutment member 
mounted on the carriage for movement between an operative position thereof 
in which it projects into the path of the actuator member and an 
inoperative position thereof, and operating means activatable to move the 
brake means into its inoperative condition and the abutment member into 
its operative position. The construction accordingly is such that, in 
carrying out a stroke setting operation of the press, with a cutting die 
to be used for subsequent cutting operations interposed between the 
platens, the switch of the stroke terminating means can be rendered 
ineffective and the operating means operated, thereby moving the brake 
means to its inoperative condition so that the moving means moves the 
carriage upwards until the abutment member engages the actuator member, 
and upon the upper platen being moved into engagement with the cutting 
die, the actuator member, engaging the abutment member, causes the 
carriage to be moved downwards on its slideway to a stroke-terminating 
position whereupon de-activation of the operating means causes the brake 
means to move into its operative position. Hence, upon upward movement of 
the upper platen, the actuator member is set apart from the switch by a 
distance corresponding to a cutting stroke of the press.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The illustrative cutting press generally resembles that described in 
British patent specification No. 1,035,816 and in appearance, may be 
similar to that shown in U.S. Pat. No. Des. 198,995, in that it comprises 
a framework which supports two columns, an upper platen 1 supported on the 
two columns, a lower platen 2 below the upper platen, and hydraulic piston 
and cylinder means (not herein shown) for moving the upper platen by 
moving the columns so that the upper platen approaches the lower platen 
whereby to effect a cutting stroke of the press. The hydraulic piston and 
cylinder means is operable at high pressure to effect a cutting stroke of 
the press or at low pressure to effect a setting operation of the press. 
The press also comprises stroke terminating means and stroke setting means 
hereinafter to be described. 
The stroke terminating means comprises a rod 4 (FIGS. 2 and 4) which 
depends from a portion of the upper platen 1 which projects beyond the 
lower platen 2. The rod 4 has an actuator member 6 (FIGS. 3, 4) projecting 
normally therefrom. The actuator member 6 is thus interconnected with the 
upper platen so that, when the upper platen is moved, the actuator member 
6 is moved in a vertical path by a corresponding amount. The actuator 
member 6, for a purpose later mentioned, has a groove 8 in the 
undersurface thereof. 
The stroke terminating means also comprises a microswitch 10 (FIGS. 2 and 
3, and indicated by chain dot in FIG. 4) which has an actuator roll 12 
which is mounted in the path of the actuator member 6 (see FIG. 3) so that 
the microswitch 10 can be operated thereby. Operation of the microswitch 
10 is effective to terminate a cutting stroke of the press by reversing 
the direction of operation of the aforementioned hydraulic piston and 
cylinder means. 
The stroke setting means of the illustrative press is arranged to bring the 
microswitch 10 to a stroke-terminating position appropriate to a cutting 
die to be used for subsequent cutting operations. The stroke setting means 
comprises a carriage 14 which is mounted for vertical movement on a 
slideway generally designated 16 (FIG. 2) adjacent to the path of the 
actuator member 6. The slideway 16 is mounted on the framework of the 
press and comprises a base plate 18, a top plate 20, two 
vertically-extending tubes 22 interconnecting the plates 18 and 20, and a 
vertically-extending rod 24 also interconnecting the plates 18 and 20. The 
carriage 14 has two projecting extensions 26 which are respectively 
secured to the tubes 22 by means of plates 27 held on the extensions 26 by 
screws 29. The extensions 26 allow the carriage to slide heightwise 
relative to the tubes 22. The rod 24 extends through the carriage 14. The 
microswitch 10 of the stroke terminating means is mounted on the carriage 
14 and its height on the carriage 14 can be adjusted by means of set 
screws 28. FIG. 2 also shows electrical connections 30 to the microswitch 
10. 
The stroke setting means also comprises brake means next to be explained, 
movable between an operative condition in which it holds the carriage 14 
against movement on the slideway 16 and an inoperative condition in which 
it allows the carriage 14 to move on the slideway 18. The brake means 
comprises a lever 32 (FIGS. 2-4) pivotally mounted within the carriage 14 
on the rod 24 and having a wedging surface 34 (FIG. 3) adapted to engage a 
stop screw 36 of the carriage 14. The lever 32 is movable between a first 
braking position in which the surface 34 bears against the screw 36 and 
consequently binds on the rod 24 thus to lock the carriage 14 on the 
slideway, and a second free position as shown in FIG. 3 in which the 
member 32 has moved counterclockwise from its first position and an 
abutment face 38 engages an abutment member 40 moving it into an operative 
position thereof. 
A solenoid 41 is mounted on the carriage 14 and has a core 43 which is 
pivotally connected to the leber 32. The arrangement is such that, when 
the solenoid is energized, it moves the lever 32 to its second position 
thus bringing the brake means to its inoperative condition. The solenoid 
41, thus constitutes operating means activatable to move the brake means 
into its inoperative condition and the abutment member 40 into its 
operative position. 
The abutment member 40 is mounted on the carriage 14 for longitudinal 
sliding movement between the operative position thereof (shown in FIG. 3) 
in which it projects into the path of the actuator member 6 and an 
inoperative position thereof in which the actuator member 6 can pass it 
without engaging it. The abutment member 40 is recessed so that it has a 
head portion 42 which can fit into the above-mentioned groove 8 of the 
actuator member 6. When the head position 42 is in the groove 8, the 
abutment member 40 is thereby prevented from returning to its inoperative 
position. The actuator member 6 and the abutment member 40 are thus 
constructed so that, while the actuator member 6 and the abutment member 
40 are in engagement, the members 6 and 40 interlock to prevent movement 
of the abutment member 40 out of its operative position. The abutment 
member 40 is urged by a coil spring 44 towards its inoperative position. 
The spring 44 is effective, when the abutment member 40 is in engagement 
with the surface 38 of the leber 32 to urge the lever 32 into its first or 
braking position. 
The stroke setting means of the illustrative press also comprises moving 
means in the form of a partly coiled tension or clock spring 46. The 
spring 46 is suspended from a bracket 48 which depends from the plate 20 
and is connected to an upward projection 50 of the carriage 14. The spring 
46 is thus arranged to urge the carriage 14 upwards on the slideway 16. 
The illustrative cutting press also comprises at the upper end of the 
slideway 16 a microswitch 52 (FIGS. 2, 4) mounted on a bracket 54 which 
depends from the plate 20. The microswitch 52 is effective, when engaged 
by the actuator member 6, to prevent operation of the hydraulic piston and 
cylnder means for moving the upper platen 1 away from the lower platen 2. 
Thus the actuated microswitch 52 serves to prevent the hydraulic piston 
and cylinder means from attempting to raise the upper platen 1 
excessively. 
The illustrative cutting press also comprises a microswitch 56 mounted on 
the plate 18 and effective, when engaged by descent of the carriage 14, to 
prevent operation of the hydraulic piston and cylinder means. The 
microswitch 56 thus serves to prevent operation of the illustrative press 
if the spring 46 fails and the carriage 14 falls to the bottom of the 
slideway 16. 
In the operation of the illustrative cutting press, a workpiece is 
positioned on the lower platen 2 with a cutting die CD (FIG. 1) on top of 
the workpiece and the hydraulic piston and cylinder means operates to 
effect a cutting stroke by moving the upper platen 1 downwards. As the 
upper platen moves, the actuator member 6 moves downwards until it engages 
the microswitch 10 whereupon the operation of the hydraulic piston and 
cylinder means is reversed. However, before operating the press as 
aforesaid, a stroke setting operation must be carried out to correctly 
position the microswitch 10 heightwise relative to the actuator member 6. 
In carrying out a stroke setting operation of the illustrative press, with 
a particular cutting die CD to be used for subsequent cutting operations 
interposed between the platens but without a workpiece between the 
platens, an operator of the press closes an electric circuit (not herein 
shown in detail) which energizes the solenoid 41. Energization of the 
solenoid 41 is also effective to render the microswitch 10 ineffective 
since a relay in the circuit to the solenoid 41 opens a contact in the 
circuit to the microswitch 10. Energization of the solenoid 41 causes the 
lever 32 to be moved to its second position (FIG. 3) in which the brake 
means is in its inoperative condition and the abutment member 40 is in the 
path of the actuator member 6. Since the brake means is not holding the 
carriage 14 against movement, the spring 46 causes the carriage 14 to move 
to the top of the slideway 16 where it is brought to rest by engagement 
between the abutment member 40 and the actuator member 6. The head portion 
42 enters the groove 8 holding the abutment member 40 in its operative 
position so that there is no possibility that downwards movement of the 
actuator member 6 will cause the actuator member 6 to push the abutment 
member 40 out of the way thus disengaging the actuator member 6 from the 
abutment member 40. 
The operator of the illustrative press next causes the hydraulic piston and 
cylinder means to operate under low pressure to move the upper platen 1 
downwards. As the upper platen moves downwards, the carriage 14 is also 
carried downwards on the slideway 16 because of the engagement between the 
actuator member 6 and the abutment member 40. When the upper platen 
engages the cutting die CD whereupon the carriage 14 is at a 
stroke-terminating position thereof, the operator de-activates the 
solenoid 41 causing the brake means to move into its operative position so 
that the carriage 14 is no held against movement on the slideway 16. The 
operation of the hydraulic piston and cylinder means is now reversed and, 
upon upwards movement of the upper platen, the actuator member 6 is set 
apart from the microswitch 10 by a distance corresponding to a cutting 
stroke of the press. 
It is found that the stroke setting means of the illustrative cutting press 
is easy to operate since the operator is only required to operate an 
electrical switch to energize and de-energize the solenoid 41.