Device for inserting bars into tubes

The invention relates to a device for inserting bars into a tube, in particular the so-called bar guide tube of a lathe. The device comprises a carriage mobile parallel to a guide arranged to support a bar in a position aligned with the tube. The carriage is provided with an appendix which intersects the guide, such that during a first stroke of the carriage, said appendix thrusts against the rear end of the bar in such a manner that this latter becomes partly inserted into the tube. The carriage also comprises a bar thrust rod mounted mobile relative thereto so that it can be disposed along the guide and aligned with the bar, so that the bar becomes completely inserted into the tube during a second stroke of the carriage.

BACKGROUND OF THE INVENTION 
This invention relates to a device for inserting bars into tubes, in 
particular bar guide tubes of lathes. 
In the mechanical machining field it is known to mass-produce mechanical 
pieces on a lathe starting from bars. In the case for example of 
multi-spindle lathes, the bar has to be inserted into a guide bar tube on 
the machine, which then successively feeds the bar. The bars, taken from a 
store and deposited on a guide axially to the guide bar tube, are inserted 
into this latter by a so-called bar thrust device which is operated by a 
drive system, for example of the chain type. 
The bar thrust device, which is disposed behind the bar and along the axis 
thereof, is often of considerable length, as in most cases it is required 
to move the rear end of the bar considerably beyond the rear end of the 
tube. The total length of the device, represented, in practice, by the sum 
of the lengths of the bar and bar thrust device, is consequently generally 
considerable, this drawback being aggravated by the fact that the device 
is disposed longitudinally to the machine tool, i.e. in the direction of 
its maximum length. In many cases, this prejudices its installation. 
SUMMARY OF THE INVENTION 
The present invention sets out to eliminate this drawback by providing a 
device for inserting bars into tubes, which is of a considerably reduced 
overall length than conventional types, while enabling the rear end of the 
inserted bar to be moved to a considerable degree into the guide tube. 
Within this aim it is possible to arrange that the device for inserting 
bars into tubes is of simple design, versatile use and economical cost, so 
that production is made advantageous in all senses. 
According to one aspect of the present invention there is provided a device 
for inserting bars into tubes, comprising a carriage mobile to and fro in 
a direction parallel to a guide arranged for supporting a bar in a 
position aligned with the tube, characterized in that said carriage is 
provided with an appendix which intersects the guide, such that during a 
first active stroke of the carriage, said appendix thrusts against the 
rear end of the bar in such a manner that this latter becomes partly 
inserted into the tube, and comprises a bar thrust rod which is mounted 
mobile on the carriage in such a manner that it can be disposed along the 
guide and aligned with the bar, so that the bar becomes completely 
inserted into the tube during a second active stroke of the carriage, 
means being provided at the rear end of the device for raising the bar 
thrust rod from the guide in order to enable a subsequent bar to be fed 
into the guide.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
With reference to said figures, the reference numeral 1 indicates overall 
the device according to the invention for inserting bars 2 into a tube 3, 
in particular a bar guide tube for example of a multi-spindle lathe. The 
bars 2 are fed one-by-one in succession from a suitable store, not shown 
on the drawing, into an upwardly open guide 4 disposed in alignment with 
the tube 3. The device 1 comprises substantially a carriage 5 which is 
mobile parallel to the guide 4 in opposing directions in operating a drive 
system 6, for example of the chain type. Stop means of known type, 
comprising electrical contacts or the like, enable the carriage 5 to be 
automatically halted at predetermined points. The carriage 5 comprises a 
flat appendix 7 of angular profile, which extends transversely to the axis 
of motion of the carriage towards guide 4 such that its end intersects the 
guide, and is slidable along it when the carriage moves. 
The carriage 5 also upperly comprises a pair of expansions 8a, b, between 
which a pin 9 is rotatably mounted with its axis parallel to the axis of 
the guide 4. A bar thrust rod 11 with its axis parallel to the axis of the 
guide 4 is fixed on one side of the pin 9 by means of a bracket 10. The 
bar thrust rod 11 is therefore rotatable with the pin 9, in such a manner 
that when the bar 2 is absent, said rod can lie by gravity inside the 
guide 4 to the front of the carriage appendix 7, i.e. on that side of said 
appendix 7 which faces the tube 3. The rod 11 is fixed to the bracket 10 
at its rear end so that the rod can be inserted almost over its entire 
length into the tube 3. 
A stem 12 for supporting a roller 13 is fixed transversely to the pin 9 on 
the opposite side to the bracket 10. The roller 13 is arranged to engage, 
at the rear end of the device, a stationary cam 14 designed to lift the 
bar thrust rod 11 from the guide 4. The operation of the device for 
inserting bars into tubes is as follows. As shown in FIG. 1, the carriage 
5 is initially at the rear end of the device where the cam 14, by engaging 
the roller 13, keeps the bar thrust rod 11 lifted. A bar 2 can therefore 
be introduced into the guide 4. 
When the carriage 5 is moved in the direction of the arrow A of FIG. 2 by 
the drive system 6, the bar 2 is urged towards the mouth of the tube 3 by 
the carriage appendix 7. During this first active stroke, the bar thrust 
rod, which is free from its engagement with the cam 14, descends to rest 
on the bar 2. 
After passing through a predetermined path, which is of length greater than 
the length of the bar thrust rod 11, the carriage 5 is halted and reverses 
its movement, while the bar 2 remains at rest in the attained position of 
partial insertion into the tube 3. During the carriage return stage (arrow 
B of FIG. 3), the bar thrust rod 11 slides on the bar 2 and at the end 
falls into the guide 4 to lie on the same axis as the bar. 
The carriage 5 now stops before the cam 14, and its direction of movement 
is again reversed (arrow C of FIG. 4). During this second active stroke, 
the bar thrust rod 11 inserts the bar deeply into the tube 3. 
This depth can be chosen in relation to the length of the rod. When the bar 
is reached its predetermined position, the carriage 5 returns to its 
initial position for the insertion of a new bar. 
It is therefore apparent that the device according to the invention has an 
overall length which is substantially reduced relative to conventional 
types. 
This length is necessarily only slightly greater than the length of the bar 
to be inserted. In spite of this, because of the double stroke of its 
carriage, the device enables the rear end of the bar to be inserted to a 
considerable extent into the bar guide tube. 
The materials, shapes and dimensions of the device can be chosen at will 
according to requirements. Moreover, all details can be replaced by others 
technically equivalent.