Tool fastening means for a press

A fastening device for enabling a tool to be slid as a unit onto a mounting table of a machine such as a press or the like to a predetermined position thereon and for enabling a displacable slide of the machine to engage in its moving direction with the upper part of the tool. For fastening the tool the device comprises slots in the table and guide bars on the lower side of the tool, the guide bars being introducable into and lockable in the slots by means of locking means on the table, and engagement means on the upper side of the tool the engagement means being introducable in the moving direction of the slide into corresponding recesses in the slide and lockable therein by means of locking means on the slide.

This invention relates to a device for fastening or mounting a tool in a 
machine such as a press, a casting machine, an injection moulding machine 
or the like, the machine comprising for mounting the tool mounting tables 
or mounting slides movable relatively each other. 
In such machines as presses of different types, injection moulding machines 
or the like use is made of tools normally comprising two parts, the first 
part of which is fastened to a stationary mounting table and the second 
part of which is fastened to a slide movably provided in the machine. The 
types of tools mentioned are made to a very high degree of precision and 
require in order not to be destroyed or to function in the way intended a 
corresponding high degree of precision regarding their mounting on the 
table and the slide. Further, the parts of the tools must be absolutely 
immovably secured to the table and the slide respectively and must be 
exactly aligned relatively each other. Finally, tools of this kind usually 
are very heavy and can typically have a weight of several hundred kilos. 
Taking the above in consideration, it is rather apparent that change of 
tool in a machine of the kind mentioned above is a timeconsuming and 
responsible work which must be done by well qualified personnel. Though 
such changes of tools are made by specially trained personnel, they 
usually may require several hours or even a whole day. This implies that 
both the machine in which the change of tool is being made and the person 
normally operating this machine are not in work during a corresponding 
period of time. 
As the time consumption when changing a tool in a machine of the kind 
mentioned above has since a long time been a well known problem attempts 
have of course been made to construct appropriate quick-fastening devices 
for the tools. These quick-fastening devices have suffered from many 
different drawbacks mainly consisting in the necessity of specially 
designing the tools for enabling them to cooperate with the clamping means 
of the quick-fastening devices. This means that tools already made can not 
be used together with such a quick-fastening device or must the tools be 
altered or rebuilt to fit the machines equipped with the quick-fastening 
device. 
Other drawbacks present with known quick-fastening devices are the 
requirement that fastening of the tool can only be effected when the 
mounting table and the slide are at a predetermined distance from each 
other, this distance must be kept with very close tolerances to make it 
possible at all to mount the tool. Other drawbacks present with 
quick-fastening devices of the prior art have been that the aligning of 
the parts of the tools relative to each other has not been possible to 
achieve automatically with a high enough degree of precision. A further 
drawback present with many types of prior known quick-fastening devices 
has consisted in the fact that they have been positioned on the upper 
surface of the mounting table of the press and on the lower surface of the 
mounting slide and that for their operation they have needed e.g. 
hydraulic fluid or compressed air. As a result of this the fastening 
devices and their operating lines have been considered bulky or 
unconvenient to handle and have made it impossible to use automatic 
feeding mechanisms to feed the press with work-pieces and remove them 
therefrom. 
Thus, the purpose of the present invention is to provide a fastening device 
for fastening a tool in a machine of the kind mentioned above the 
fastening device according to the invention being so designed as to avoid 
the drawbacks present with the above devices of prior art. 
According to the invention this purpose is achieved if a fastening device 
for fastening a tool in a machine such as a press, a casting machine, an 
injection moulding machine or the like comprising for mounting the tool 
tables or slides movable relatively each other is characterized by 
engagement means provided on the surfaces of the tool facing the table or 
the slide the engagement means being introducable into corresponding 
recesses provided in the table or the slide and by locking means provided 
on the table or the slide for cooperating with the engagement means the 
locking means being movable between locking positions in locking 
engagement with the engagement means and positions of non-engagement where 
the engagement means are movable into and out of the recesses. 
In one embodiment of the invention particularly intended for a vertically 
working press there is according to the invention foreseen that the 
recesses of the table have the shape of slots into which the engagement 
means provided as guide bars are introducable in the longitudinal 
direction thereof and in parallel with the plane of the table and that the 
engagement means for engaging the slide are introducable into the recesses 
thereof in the moving direction of the slide. By these measures there is 
achieved the great advantage that the tool can be placed as a unit, e.g. 
on brackets fastened to the table and having the same level of height as 
the upper surface thereof by means of a lifting truck or another lifting 
device. From this position the tool can be slid to its correct position on 
the table, use may be made of an antifriction agent or device. In the 
correct position of the complete tool it is then possible to lower the 
slide of the press to engage the upper part of the tool. 
The embodiment indicated above is further characterized in that the guide 
bars are defining undercut grooves in which are engaging heads of the 
locking members provided on the table, the locking members being movable 
perpendicularly to the plane of the table to accomplish locking and that 
the engagement means for cooperating with the slide of the press are 
defining undercut pockets into which are axially introducable heads on the 
locking members of the slide the heads being engageable with the 
engagement means by rotation and lockable by displacement perpendicularly 
to the plane of the slide. 
To eliminate the risk that the tool gets loose and possibly destroyed e.g. 
at failure of current breakage of any pressure line in the machine or the 
like there is, according to the invention, foreseen that the locking 
members are movable to their locking positions under influence of spring 
means and to their non-locking positions under influence of a pressurized 
fluid.

In FIG. 1 there is shown one example of a mounting table of a machine for 
carrying the invention into effect. It is apparent from the figure that 
the table 1 in a conventional manner is provided with T-grooves 2 for 
making it possible to use conventional clamping means in a case where 
tools are to be used not provided with the engagement means necessary for 
carrying the invention into effect. It is also apparent that the table 1 
is provided with elongated recesses 3 parallel to the T-grooves. From the 
bottom surfaces of the recesses 3 there are upwardly protruding locking 
members 4 having heads 5 intended to engage with the engaging means. 
Preferably, the recesses 3 are of rectangular cross sectional shape and 
have open ends at one edge 6 of the table 1. The other ends 7 of the 
recesses 3 are preferably closed or provided with abuttment means. In this 
area there could also be provided an indicating apparatus the purpose of 
which will be described below. Further, at 9 there is in FIG. 1 indicated 
operating devices for locking members 4, these operating devices being 
situated at the lower side of the table or being built-in into the 
material of the table. 
In FIG. 2 there is schematically shown a cross-section approximately along 
arrows A--A in FIG. 1. Thus, in FIG. 2 the reference numeral 10 refers to 
the lower part of the tool, the reference numeral 1 as is the case in FIG. 
1 refers to the table and finally the reference numeral 11 refers to a 
cylinder which is a part of the operating device 9 for the locking member 
4. 
From FIG. 2 is evident that the lower part 10 of the tool is provided with 
guide bars 13 fastened thereto by means of screws 12. The vertical outer 
surfaces 14 are positioned at such distance from each other that the guide 
bars 13 with a high degree of precision fit in the recesses 3 of the table 
1. Though not shown in FIG. 2 it is clear that the lower part 10 of the 
tool is provided with four guide bars 13, these guide bars being in pairs 
received in the elongated recesses 3 of the table. The surfaces 15 facing 
each other on the guide bars 13 are stepped so that the bars between them 
are defining a T-shaped groove. As an alternative the T-groove and the 
vertical surfaces 14 may be provided on integrally made members. 
As is apparent from FIG. 2 the locking member 4 is extending through the 
table 1 and is at its upper end provided with a head 5 extending to such a 
level above the bottom surface of the elongated recess 3 that the upper 
end surface of the head 5 never protrudes above the upper surface 16 of 
the table 1. Further, the head 5 is of such dimensions that it can be 
received in the T-shaped groove defined by the guide bars 13 and the lower 
part 10 of the tool. 
As is clearly evident from the drawing the locking member 4 is extending 
through the table 1 and is at its lower end connected to a piston 17 
received in a cylinder 11. The piston is provided with sealing rings 18 of 
adequate design for sealing the space 19 between the lower side of the 
piston and the bottom of the cylinder. Between the upper side of the 
piston and the lower side of the table 1 there are provided spring washers 
22 of a suitable number, the spring washers urging the piston and the 
locking member 4 downwardly with a considerable force (in the range of 
5-10000 Kp). To counteract the force of the springs 22 the cylinder 11 has 
an inlet 20 for fluid under pressure by means of which the piston 17 can 
be displaced upwardly so that the head 5 of the locking member 4 can be 
brought to a position (shown in FIG. 2) in which no engagement occurs 
between the lower side of the head and the stepped surfaces 21 of the 
guide bars 13. Inversly, it is possible by reducing the pressure in the 
space 19 to move by means of the spring washers 22 the locking member 4 
downwardly so that the lower side of the head 5 is pressed against the 
stepped surfaces 21 of the guide bars with the force mentioned above. In 
this condition the lower part 10 of the tool will be pressed with great 
force against the table 1 and will securely be held in this position. 
Though not shown on the drawings the slide of the press which in the 
machine described so far is positioned vertically above the table of the 
press and which is displaceable in the vertical direction relative to the 
table by means of a conventional fluid-actuated ram 42 (FIG. 4), the 
table, may on its lower side be provided with T-grooves corresponding to 
the T-grooves 2 on the table. However, the slide is not provided with any 
elongated recesses corresponding to the recesses 3 of the table. 
In FIG. 3 there is shown a cross sectional view of the slide of the press 
corresponding to the cross sectional view A--A of the table. Thus, in FIG. 
3 the reference numeral 23 refers to the slide of the press, the reference 
numeral 24 refers to the upper part of the tool while the reference 
numeral 25 refers to the locking means of the slide and the reference 
numeral 26 refers to a cylinder being a part of the locking means 25. 
According to the invention there is on the upper surface of the upper part 
24 of the tool fastened by means of screws a cylindrical member 28 which 
is shown in detail in FIG. 5, seen in the direction of arrow B. With a 
certain play the cylindric member 28 can be received in a corresponding 
bore 29 in the slide 23 and is internally provided with a cylindrical 
recess 30 having connection with the upper surface of the cylindric member 
28 via an elongated opening 31. The recess 30 has abuttment surfaces 32 
defining the upper end thereof. 
As is evident from FIG. 3 the locking means 25 extends right through the 
slide 23 and is in its lower end provided with a head 33 having a shape 
corresponding to the shape of the elongated opening 31. However, the 
dimensions of the head 33 are slightly smaller than the dimensions of the 
opening so that the head can be inserted through the opening and received 
in the recess 30. 
At a mid-position of the locking member 25 there is provided a protruding 
flange 34 against the upper surface of which is abutting a piston 35 
displacable in a cylinder 26 and sealed thereto by means of sealing rings 
36. The end wall of the cylinder 26 and the upper surface of the piston 35 
define a space 37 which can be exposed to pressure by means of a 
pressurized fluid supplied via an inlet 38 whereby the piston is pressed 
downwardly. Between the lower surface of the piston 35 and the upper 
surface of the slide 23 there is provided spring washers 39 to a suitable 
number. The spring washers 39 are urging the locking member 25 upwardly 
with a considerable force when the space 37 is released of pressure. 
Inversly, it is possible to displace the piston 35 downwardly against the 
action of the springs 39 by supplying fluid under pressure to the space 
37. This displacement in vertical direction will also impart a 
corresponding displacement to the locking member 25 and the head 33 
thereof. 
The piston has in a central portion thereof a through boring through which 
extends a portion of the locking member 25, the member being rotable 
relative to the piston 35. The upper end of the locking member 25 is 
provided with a sprocket wheel 40 the lower surface of which abuts the 
upper surface of a central hub portion of the piston 35. By displacing the 
chain 41 as indicated by arrow C it is possible to rotate the sprocket 
wheel 40 and the locking member 25 so that the head 33 thereof is rotated 
to a position shown in broken lines 42 in FIG. 3. In this position the 
upper surfaces of the head 33 are disposed beneath the abuttment surfaces 
32 of the cylindrical member 28 (the head has been rotated 90.degree. from 
the position shown in FIG. 5). By displacing the locking member 25 
upwardly in this position of rotation the head 33 will engage the 
cylindrical member 28 whereby the upper part 24 of the tool is pressed by 
the force excerted by the springs 39 to a fastening engagement with the 
lower surface of the slide 23. 
In the position shown in FIGS. 3 and 5 the head 33 of the locking member 25 
can be introduced into and withdrawn out from the elongated opening 31 and 
the cylindrical recess 30 by displacing vertically the slide relative to 
the upper part 24 of the tool. 
To achieve the movement of the chain 41 as indicated by arrow C the upper 
side of the slide 23 is equipped with the devices shown in FIG. 4. Thus, 
this figure shows four cylinders 26 on the upper surfaces of which the 
sprockets 40 are indicated meshing with the chain 41 which is extending in 
a loop around the four sprockets. In an interruption 43 in the chain 41 
the ends thereof are fastened to a yoke 45 by means of at least one 
adjustment member 44 the yoke being fastened to the ends of a piston rod 
46 which extends through a pneumatic or hydraulic cylinder 47. By 
supplying pressurized fluid to the cylinder 47 it is possible to displace 
the piston rod 46 longitudinally and thereby to impart rotation to the 
four sprocket wheels 40. Further the design is such that vertical 
displacement of the chain 41 caused by the vertical displacement of the 
pistons 35 in the cylinders 26 is taken up by turning the yoke 45 around 
the longitudinal axis of the piston rod 46. 
The inventive device works in the following manner: 
When mounting a tool in the press described above the tool can be 
transported from a storage place to a position at the same level as the 
table 1. This could either be achieved by means of a stationary provided 
transporting equippment or by a lifting truck or the like. In the latter 
case the tool is suitably placed on two protruding brackets or arms 
fastened to the table in alignment with the two rows of roller members 48 
which protrude somewhat above the upper surface of the table but which 
also can be depressed into it. Preferably, in this alternative the 
brackets are also provided with corresponding roller members by means of 
which the tool easily can be displaced to such a position that the guide 
bars 13 fastened to the lower side of the tool are aligned with the 
elongated recesses 3 in the table. Before the tool is rolled onto the 
table 1 by means of the roller members 48 there must be assertained that 
the locking members 4 of the table are in their upper, free positions 
which is accomplished by supplying pressurized fluid to the spaces 19 
below the pistons 17 so that the spring washers 22 are compressed. 
Preferably, this can be done completely automatically when the hydraulic 
system of the machine is set for tool exchange. When the locking members 4 
are in their upper positions it is possible to manually without any 
considerable effort slide the tool onto the table 1 while the tool is 
guided to an exactly aligned position on the table by engagement between 
the side surfaces of the guide bars 13 and the elongated recesses 3. When 
the tool has reached such a position that the inner ends of the guide bars 
13 are engaging the indication means 8 preferably located at the inner 
ends of the recesses 3 it is made possible or is automatically arranged 
that the pressure present in the spaces 19 is relieved to such a degree 
that the spring washers 22 are displacing the locking means 4 downwardly 
so that the lower portion of the tool is pressed against the table to a 
locking engagement therewith. To enable this the roller members 48 are 
spring loaded by springs 50 so that they can be depressed into their 
seats. When the spaces are completely relieved of pressure the slide 23 is 
lowered, preferably automatically, so that the cylindrical members 28 on 
the upper side of the tool is received in the recesses 29 in the slide. At 
this moment the heads 33 of the locking members 25 of the slide are 
rotated to such positions that they can be introduced through the 
elongated openings 31 in the cylindric members 28. Then, when a certain 
pressure has been achieved in the main cylinder of the press (the cylinder 
operating the slide) there is automatically achieved or is made possible 
manual operation of the cylinder 47 on the upper side of the slide so that 
the heads 33 of the locking members 25 are rotated 90.degree.. Then the 
pressure present in the spaces 37 is relieved so that the spring washers 
39 with great force are urging the locking members 25 upwardly said force 
via the upper surfaces of the heads 33, the abuttment surfaces 32 of the 
cylindric members 28 being transmitted to the upper part 24 of the tool so 
that said part is pressed to a locking engagement with the lower side of 
the slide 23. When the spaces 37 are completely relieved of pressure the 
tool has been mounted in the press and this is ready for operation. 
When removing the tool from the press the working order is the opposite. 
Thus, the tool is first closed with the last workpiece left in the tool to 
guarantee centering of the two tool parts 10 and 24 when mounting the tool 
next time. When the tool has been closed the spaces 37 are exposed to 
pressure whereby the pistons 35 are pressed downwardly and the heads 33 of 
the locking members 25 are rotated to their free positions (FIG. 5) 
relatively the abuttment surfaces 32. Then the slide 23 of the press is 
elevated to its uppermost position and also the spaces 39 in the cylinders 
11 are exposed to pressure so that the pistons 17 and thus the locking 
members 4 are displaced upwardly to their free positions. When this 
displacement is finished the spring loaded roller members 48 will lift the 
tool as a unit a short distance above the table 1 so that the tool easily 
can be slid out onto the brackets carried by the roller members. 
The invention may also with great advantages be carried into effect in 
injection moulding machines. In this alternative the fastening surfaces of 
the stationary table and the slide are not horizontal but vertical which 
implies that the recesses 3 in the table should have their open ends 
facing upwardly. The method of changing tool is in other respects quite 
analogous. Thus, the tool is lowered by means of a jack or other suitable 
lifting device in such a manner that the tool is sliding along the surface 
of the stationary table and is guided by cooperation between the guide 
bars and the elongated recesses provided in the table. 
Naturally the invention also may be carried into effect in other types of 
machines where a tool with a high degree of precision must be fastened. 
Thus, a tool for pressure die casting can with great advantages be 
fastened in a pressure die casting machine. Further, welding fixtures of 
different kinds can be mounted in automatic lifting- and operating 
machines or the like. 
The invention can be modified within the scope of the following claims. 
Thus, it is possible to use in the table and the slide a number of locking 
means other than four e.g. two, six, eight etc. If required these locking 
means can of course be arranged in more than two rows, e.g. three or four 
if the table and the slide are of big dimensions. Further, the elongated 
recesses in the table may have both their ends open the indication means 
in such a case having a construction different from that mentioned above. 
According to the invention it is also possible to achieve the rotation of 
the locking members of the slide in a manner different from what has been 
described. Thus, it is possible to use a separate operating device for 
each of the locking means on the slide said operating device may be 
designed in any way e.g. as a cylinder, a solenoid or the like. 
According to the invention it is also possible to convert a machine already 
present if it is provided on its table and slide with additional plates 
incorporating the fastening device of the invention. Such plates will also 
serve as new tool fastening surfaces of the machine.