Chain magazine for shop machines

A chain magazine for shop machines, especially for apparatus for handling workpieces, including at least one endless rotating chain, preferably a roller chain, that is guided over sprocket wheels. Holders, for accommodating tools, workpieces, or the like, are mounted on the chains via connectors that are provided on at least two places of attachment, preferably pins, of chain links of the chains. Each connector, in a portion thereof that is disposed beyond the sprocket wheels, is provided with at least one support part via which the connector is supported against at least an adjacent chain link of the chains.

BACKGROUND OF THE INVENTION 
The present invention relates to a chain magazine for shop machines, 
especially for apparatus for handling workpieces, and includes at least 
one endless rotating chain, preferably a roller chain, that is guided over 
sprocket wheels, with holders, for accommodating tools, workpieces, or the 
like, being mounted on the chain via connectors that are provided on at 
least two places of attachment, preferably pins, of chain links of the 
chains. 
Via such chain magazines, the tools, workpieces, or the like that are 
accommodated in the holders are brought into the zone of a changer that 
removes the tools, etc., from the holders and places them into the shop 
machine. So that the changer can reliably remove the tool, workpiece, or 
the like from the holder, it is necessary that in the grasping position 
the tools etc. assume a precise position relative to the changer. Since 
the holders must accommodate tools, workpieces or the like that have 
different weights, holders that are thus equipped have correspondingly 
different weights. For this reason, in the changing position the holders 
tilt to different extents, so that depending upon the holder, different 
changing positions are provided. This tilting movement is possible because 
the transport chain is flexible and has a certain amount of play in its 
guide means. If the holders are equipped with very heavy tools, 
workpieces, or the like, these holders then assume the deepest position in 
the changing position, whereas empty holders, as a consequence of their 
light weight, assume the highest position in the changing position. Due to 
these varying positions of the holders in the changing position, problems 
arise during the changing process. 
It is therefore an object of the present invention to embody a chain 
magazine of the aforementioned general type in such a way that the tools, 
workpieces, or the like that are accommodated in the holder assume as 
exact a position as possible in the grasping position.

DESCRIPTION OF PREFERRED EMBODIMENTS 
Referring now to the drawings in detail, as shown in FIG. 1 the chain 
magazine for shop machines, especially for apparatus for handling 
workpieces, is provided with holders 1 for tools and/or workpieces 2. By 
means of connectors 3, the holders 1 are secured on chain belts or endless 
chains 4, 5, which are preferably roller chains. The chains 4, 5 are 
guided over sprocket wheels 6 and 7. In conformity with the cycle that has 
been introduced, the chain magazine is moved in such a way that the 
desired tool 2 is disposed at a prescribed position at which the tool can 
be removed from the holder 1 via a tool changer and can be inserted into 
the spindle of the shop machine in question. 
The holders 1 are basically known and will for this reason not be described 
in greater detail. As can be seen more clearly from FIG. 2, the holders 
have receiving means 8 for a conical portion 9 of the tool or workpiece 2. 
In the illustrated embodiment, as shown in particular in FIG. 2, each 
holder 1 is secured via two connectors 3 to the endless chains 4 and 5 
respectively. These endless chains are of the same construction, each 
being embodied as a twin roller chain pursuant to DIN 8187/ISO R 606; each 
of the endless chains 4, 5 has two opposed outer link members 11, 12 that 
are interconnected by two pins 13, 14. Outer link members 11, 12 that are 
adjacent to one another in the longitudinal direction of the chain are 
pivotably interconnected by respective inner link members 15 and 16 that 
are also provided in pairs. The inner link members 15, 16 that in the 
longitudinal direction of the chain connect adjacent outer link members 
11, 12 are similarly pivotably connected with the outer link members 11, 
12 via the adjacent pins 13 and 14. Disposed in a known manner on the pins 
13, 14 in the region between the inner link members 15, 16 are respective 
rollers 17. The sprocket wheels 6, 7 mesh in a known manner between 
adjacent rollers of the endless chains 4 and 5. 
As shown in FIG. 2, the pins 13, 14 of the two parallel endless chains 4, 5 
are lengthened or extended toward one another beyond the chains. Loosely 
seated on the pins 13, 14 are the connectors 3, which are provided with 
appropriate holes 18 and 19 (see FIG. 3). As shown in FIG. 2, the pins 13, 
14 extend beyond the connectors 3 in a direction toward one another. Each 
holder 1 is held on the endless chains 4 and 5 by two connectors 3. In the 
illustrated embodiment, the connectors 3 are separate from the holder 1 
and are detachably connected therewith. This enables an easy assembly of 
the holders because first the connectors 3 can be successively placed upon 
the projecting pins 13 and 14, the spacing of which from one another is 
greater than the length of the connectors 3. Subsequently, the holder 1 
can be placed upon the two connectors 3 and secured thereto. 
The connectors 3 are placed upon the pins 13 and 14 in such a way that they 
are disposed at the level of the outer link members 13, 14 of the endless 
chains 4, 5 (see FIG. 2). In order to be able to reliably secure the 
holder 1 to the two connectors 3, that side of the connectors that face 
the holder 1 is provided with a plate-shaped widened portion 20 against 
which the holder 1 rests. When viewed in the direction of the illustration 
of FIG. 3, the connector 3 has a rectangular main body 21 in which the two 
holes 18 and 19 are provided. Two threaded sleeves 22 and 23 are placed 
into the main body 21 on that side that is provided with the widened 
portion 20; the screws for connecting the holder 1 are screwed into the 
sleeves 22, 23. 
Due to the play of the chain guides, and due to the flexibility of the 
endless chains 4, 5, which manifests itself in particular when the holders 
1 are subjected to different loads, the holders 1, in the horizontal 
position illustrated in FIG. 1 in which the chain strands extend 
vertically, are inclined slightly downwardly, so that a position deviation 
of the tool or workpiece 2 from the desired position by an angle .alpha. 
occurs. Depending upon the weight of the holder 1 and/or of the play of 
the chain links, different position deviations .alpha. result. In order to 
keep the position deviation .alpha. as small as possible, and 
advantageously to even completely eliminate the same, the connector 3 is 
provided with a support part 24 via which the holder 1, in the tool or 
workpiece changing position, is supported against the endless chains 4, 5 
in such a way that no position deviation .alpha. occurs. The support part 
24 is embodied in such a way that it is supported on the pin 14 of the 
adjacent chain link (see FIG. 1). 
If the holder 1 is disposed in the left strand 25 in FIG. 1, and the 
sprocket wheels 6, 7 turn in the direction of the arrow 26, the support 
part 24 is then supported against the pin 13 of the leading chain link as 
viewed in the direction of rotation of the chains 4, 5. On the opposite 
side of the main body 21, the connector 3 is provided with a further 
support part 28 that in the other strand 27 of the endless chains 4, 5 is 
supported on the pin 13 of the trailing chain link as viewed in the 
direction of rotation of the endless chains 4, 5 (see FIG. 1). 
The support parts 24, 28 are provided on the oppositely disposed narrow 
sides of the main body 21, and are embodied in a mirror symmetrical manner 
relative to the transverse central plane of the connector (see FIG. 3). As 
a consequence of this symmetrical arrangement, the same connector 3 can be 
alternatively used for connection to the chain 4 or the chain 5. As can be 
seen from FIG. 2, the main body 21 and the support parts 24, 25 are 
disposed in the region adjacent the chain links of the endless chains 4, 
5, so that these support parts cannot come into contact with the chain 
links and the sprocket wheels 6, 7. Adjoining the oppositely disposed 
sides of the main body 21 at a slight distance from the widened portion 20 
are inclined top surfaces 29, 29' of the support parts 24 and 28 
respectively (see FIG. 3). These inclined surfaces extend at an angle to 
one another and merge via an obtuse angle into relatively short end faces 
30, 30' that extend parallel to one another. Oppositely disposed from the 
top surfaces 29, 29', the support parts 24, 28 are provided with 
undersides 31, 31' that converge from the pertaining top surfaces, so that 
the support parts 24, 28 preferably continuously widen from the end faces 
30, 30' in a direction toward the main body 21. In the vicinity of the end 
faces 30, 31 the support parts 24, 28 are provided on the undersides 31, 
31' with a partially circular recess 32, 32' into which the respective 
pins 13 or 14 of the pertaining chain link engage in the support position 
(see FIG. 1). The radius of curvature of the recess 32, 32' preferably 
corresponds to the radius of the pins 13, 14, so that in the support 
position the support part 24, 28 rests over a large surface against the 
respective pin. As shown in FIG. 1 the length of the two support parts 24 
and 28 of the connector 3 is such that in the support position the 
connector 3 rests not only against the pin 14 of the leading chain link 
but also against the pin 13 of the trailing chain link. The holder 1 is 
optimally supported in this way. If the holder 1 assumes the horizontal 
left or right position in FIG. 1, it is then supported via the appropriate 
support part against the adjacent chain link, so that the aforementioned 
position deviation .alpha. does not occur at all or at most occurs to only 
a slight extent. As a result, the tool or workpiece 2 that is disposed in 
the holder 1 assumes a position that is optimum for being grasped. Since 
the support parts 24 and 28 each widen from the end faces 30, 30' in a 
direction toward the main body 21, they are able to carry an adequate 
load. As shown in FIG. 1, the support length 33, as measured between the 
pin 14 of the leading chain link and the bolt 14 that is the furthest 
therefrom in that chain link on which the connector 3 is held, is greater 
than the chain pitch 34. 
The length of the support parts 24, 28 can also be such that they are also 
supported against the next chain link plus one. However, this presupposes 
that two chain links are provided between successive holders 1. In the 
illustrated embodiment, only one chain link is disposed between adjacent 
holders 1. 
As the endless chains 4, 5 are guided about the sprocket wheels 6, 7, the 
support parts 24, 28 are raised from the pins 13, 14 of the corresponding 
chain links (upper position of the holder 1 in FIG. 1). As soon as the 
endless chains 4, 5 have been guided about the sprocket wheels, the 
support parts 24, 28 are again supported against the pins of the 
corresponding chain links. This support is effective in any desired chain 
installation position. 
As shown in FIG. 1, beyond the sprocket wheels 6, 7 the chains 4, 5 are 
guided in a known manner in guide rails 35 and 36, which end at a slight 
distance from the respective sprocket wheel 6, 7. As a consequence of the 
support parts 24, 28, the length of the connectors 3 in the longitudinal 
direction of the chain is such that these connectors bridge the distance 
between the end or beginning of the guide rails 35, 36 and the sprocket 
wheels 6, 7. This has the advantage that the transition of the chains 4, 5 
from the sprocket wheels 6, 7 to the rails 35, 36 is spanned by the 
connectors 3. This results in a very quiet running of the chain, since as 
a consequence of the spanning or bridging, the oscillation or buckling of 
the chain in the critical region between the sprocket wheel and the guide 
rail is considerably reduced. 
The connector 3 is advantageously made of plastic, although it can also be 
made of any suitable material. With an appropriate choice of material for 
the connector 3, especially if is made of plastic, the running noise can 
be further reduced by favorable damping characteristics. Since as a result 
of the described configuration of the holder 1 with the connectors 3 
conventional DIN chains, chain sprockets, and chain guides can be used, 
the chain magazine can be produced in a very economical manner. 
In the embodiment that is illustrated and described, the endless chains 4, 
5 extend vertically; these chains could also extend at an angle to the 
horizontal. Also with such a position the aforementioned position 
deviation .alpha. occurs, which is counteracted by the use of the 
connectors 3 in the manner described. 
A further important advantage of the inventive connectors 3 is that as the 
endless chains 4, 5 rotate, a support of adjacent chain links against one 
another is effected via the connectors 3. This results in a very quiet 
running of the endless chains, which in turn has a positive effect upon 
the operational precision of the machine, because the vibrations that 
occur with the heretofore known chain magazines during running of the 
endless chains is thereby avoided, or at least is considerably reduced. 
In the illustrated embodiment, the connectors 3 are separate parts from the 
holder 1. However, the connectors could also be integrally formed with the 
holders 1. In addition, it is not absolutely necessary to have two 
connectors 3 for the holder; depending upon the structural configuration, 
the holders 1 could also be connected to the corresponding chain or chains 
with only one connector 3 or with more than two connectors. 
A further exemplary embodiment of the inventive connector is illustrated by 
dashed lines in FIG. 3. In this embodiment, the main body 21 is enlarged, 
resulting in a greater support surface for the holder 1. In such a case, 
the threaded sleeves 22 and 23 would be provided in the enlarged end 
region of the connectors 3. In other respects, this embodiment of the 
inventive connector fulfills the same function as does the connector that 
is illustrated by solid lines in FIG. 3. 
The present invention is, of course, in no way restricted to the specific 
disclosure of the specification and drawings, but also encompasses any 
modifications within the scope of the appended claims.