Drafting assembly for a spinning machine

A drafting assembly whose lower belt is laterally guided by a guide element having a pair of side walls joined by a web and more unitarily from a synthetic resin. The web lies outside the loop of the lower belt and in the upper belt or adjacent the lower belt. The element is held against lateral movements by abutments which can be lateral flanks of the rollers or a guide element for the upper belt. The element is prevented from twisting or rotation by engagement with a stationary turnover rail over which the lower belt passes.

CROSS REFERENCE TO RELATED APPLICATION 
This application is related to my commonly assigned copending application 
Ser. No. 697,733 filed Feb. 4, 1985 and entitled Spinning Machine Drafting 
Frame. 
FIELD OF THE INVENTION 
My invention relates to a drafting or drawing assembly for a spinning 
machine and, more particularly, to a drafting assembly which comprises a 
stationary turnover rail which cooperates with a lower roller about which 
a lower belt passes and with an upper roller about which an upper belt 
passes, the roving, fiber, yarn or sliver being passed between these belts 
in a spinning frame. More particularly, the invention relates to improved 
guidance for the lower belt of such an assembly. 
BACKGROUND OF THE INVENTION 
Drafting assemblies of the aforedescribed type are illustrated, for 
example, in the above-identified application and serve to draw out the 
roving or yarn which is to be spun in the spinning frame upon which one or 
more such assemblies may be mounted for each of the spinning stations. In 
the past means has been provided to laterally guide the lower belts and 
prevent them from shifting off the respective roller along the turnover 
rail which may be common to a number of such assemblies arrayed along the 
spinning frame for association with the respective spinning station. 
The lower roller of the assembly is generally located in a fixed position 
on the spinning frame and to provide lateral guidance of a lower belt 
which passes around such a roller, it has been proposed to utilize a 
retaining cage or the like. The cage must be inserted through the loop of 
the lower roller. This complicates matters because it is desirable to be 
able to remove or to clean the cage. 
The problem of removing such cages is complicated because the turnover rail 
itself must be passed through the loops of the lower belts of the entire 
set of assemblies to which this rail may be common. In the past complex 
guide systems had to be provided or arrangements had to be made to enable 
disassembly of the lower roller or rail to allow the lateral guide means 
to be inserted, replaced, cleaned or maintained. 
OBJECTS OF THE INVENTION 
It is, therefore, the principal object of the present invention to provide 
a drawing assembly for the drafting means of a spinning frame whereby 
these disadvantages are obviated. 
A more specific object of this invention is to provide improved lateral 
guide means for the lower belt of a drafting assembly which enables the 
lateral guide means to be cleaned, replaced or maintained in a 
nonproblematic manner. 
Still another object of my invention is to provide a drafting assembly of 
the type described with improved lateral guide means for the lower belt 
such that replacement and cleanining can be effected with comparative 
ease. 
SUMMARY OF THE INVENTION 
These objects and others which will become apparent hereinafter are 
attained, in accordance with the present invention, in an assembly which 
provides a lateral belt guide for the lower belt of the assembly, the 
guide comprising a pair of side walls lying in planes parallel to one 
another and bridged by a transverse web which lies externally of the lower 
belt and can be positioned so that the side walls closely flank and 
laterally guide the lower belt at respective guide locations while at 
other locations, the guide element is in engagement with or is engageable 
with abutments fixed with respect to the assembly while at other locations 
the element is retained against rotation with the belt by engagement with 
the turnover rail. The web can lie externally of the lower belt in this 
construction and thus the lateral guide element as a unit can be radially 
replaced or cleaned. 
The abutments against which the lateral walls can brace can be fixedly 
located parts of the assembly and in a preferred embodiment of the 
invention, the flanks defined by these side walls can be prevented from 
shifting laterally by abutment with the flanks of the upper roller, the 
flanks of the running surface of the lower roller or lateral parts of an 
upper belt cage if one is provided. 
In an especially preferred construction of the invention, the lateral walls 
in the web are united into a member which is passed through the loop of 
the upper belt. Since the upper belt does not generally pass around any 
fixed turnover rail, the upper belt can be easily removed or detensioned 
by comparison with the lower and thus removal and replacement of the 
lateral guide element is greatly simplified. 
In an alternative construction of the invention the lateral walls project 
over the edges of the upper and lower belt, i.e. project from above 
downwardly over the edges of the lower pass of the upper belt or project 
from a side over the edges of the belts with the projecting portions of 
the lateral guide element resting against the turnover rail. In this case, 
the turnover rail prevents rotation or twisting of the lateral guide 
element and the lateral movements are prevented by the side walls and 
their engagement with the flanks of the rollers or the flanks of the upper 
belt. No additional abutments or retainers are required and a simple 
threading of the lateral guide element in the loop of the upper belt will 
position the guide element for the purposes of this invention. 
According to another feature of the invention the lateral walls engage from 
above over the edge of the upper and lower belts and from below over an 
upper belt cage while the lower edges of the side walls rest from above 
upon the turnover rail. In this case, the abutments are not formed by the 
upper roller but by parts of the upper belt cage for the side walls of the 
lower belt guide of this invention. 
In yet another configuration of the invention, the side walls are formed as 
upwardly cut away rings and the web is a cylindrical segment. Here the web 
can be provided around and along the rear of the lower roller and the 
turnover rail can extend into the cutout of the lateral walls to restrict 
rotation of the lower belt guide element. 
When the rings have an angular extent or circumferential dimension which is 
somewhat greater than a semi-circle, they can be clipped over the lower 
roller and thus can be retained thereon against movement away from the 
stationary rail. 
For this purpose, the lateral guide element can be composed of a somewhat 
elastic synthetic resin, preferably a low-friction synthetic resin which 
can be injection-molded. Nylon and polytetrofluoroethylene can be used to 
fabricate the lateral guide element as well. 
According to another feature of the invention, the rings, i.e. the side 
walls, overlap the flanks of the running surface of the lower roller and 
at the same time the edges of the lower belt. Alternatively, the lateral 
guide element can be so formed that the rings overlap the edges of the 
lower belt and the upper belt as well as the flank of the upper roller. In 
this latter case the flanks of the upper roller form the abutments.

SPECIFIC DESCRIPTION 
In a first embodiment of the invention illustrated in FIGS. 1-3 and 3A, the 
drafting assembly 1 forming the terminal drafting unit of a drafting frame 
(see the above-mentioned copending application) comprises a first lower 
roller 2 and a second lower roller 3. The shaft 4 of the lower roller 2 
and the lower roller 3 are journaled in the machine frame or support shown 
in dot-dash lines and represented at 5. 
The lower rollers 2 and 3 cooperate with upper rollers 6 and 7. A loading 
arm or carrier 8 for pressing the upper rollers downwardly toward the 
lower rollers has been shown in dot-dash lines and may be of the 
construction illustrated and described in application Ser. No. 697,733 
which also describes the overall operation of such a drafting frame. 
An endless upper belt 9 passes around the upper roller 7 while an endless 
lower belt 10 passes around the lower roller 3, the upper belt having a 
lower pass and the lower belt having an upper pass, these passes meeting 
to entrain the yarn between them. 
The upper belt is guided over an upper belt cage 11 of conventional design 
which has a pair of retaining arms 12 passing over the shaft 13 of the 
upper roller and flanking the running surface thereof adjacent the flanks 
22 and 23. 
To avoid confusion, the upper cage 11 has been omitted in the view 
represented in FIG. 2. 
The upper cage 11 also has a pair of lugs 14 which engage the opposite 
edges of the belt 9 to prevent this belt from shifting laterally, i.e. 
parallel to the axis of the shaft 13. 
The lower belt 10 not only passes over the lower roller 3 but also around a 
continuous and stationary turnover rail 15, around which the belt returns 
from the upper pass. Above the turnover rail 15 and in accordance with 
this invention, I provide a lateral guide element 16 for the lower belt 
10. The lower guide element 17 comprises (see especially FIGS. 3 and 3A) a 
pair of parallel planar side walls 18 and 19 which are integral with and 
hence interconnected by, a web 17. The lateral guide elements 16 may be 
injection molded from synthetic resin. 
The side walls 18 and 19 are so formed and arranged that they engage the 
edges 20 and 21 of the lower belt 10 at certain locations, e.g. adjacent 
the web 17, and at other locations engage the flanks 22 and 23 of the 
upper roller 7, these flanks forming abutments restricting the lateral 
mobility of the guide elements 16. 
The flanks 22 and 23 here form spatially fixed abutments for the side walls 
18 and 19 of the guide element 16 to prevent the belt guide element 16 
from twisting or canting. The side walls 18 overlap or project over the 
edges of the upper and lower belts 9 and 10 sufficiently to enable the 
lower edge 24 of each side wall 18 and 19 to rest upon the turnover rail 
12 from above. 
Bulges 16a and 16b of these side walls flank the rise 15a of the rail 15 so 
that transverse shiftability of the lateral guide element 16 is precluded. 
As noted, the element 16 is a form-stable injection molding of a low 
friction synthetic resin material. The web 17 is received in the loop of 
the upper belt 10 so that it can constitute a retainer for the latter belt 
as well. 
A second embodiment of the invention has been illustrated in FIGS. 4 and 5. 
The drafting assembly 25 of these FIGURES comprises a lower roller 3' 
carried by a shaft 26. In this construction, the lateral guide element 16' 
has a somewhat different form. Here the side walls 18' and 19' are united 
by a web 17' inserted through the loop of the upper belt 9. The side walls 
18' and 19' overlap or extend over the edges 9 and 10 from above so that 
the edge 24' rests from above on the turnover rail 15. From below, the 
side walls engage over the upper belt cage 11 so that the latter can form 
the spatially fixed abutment for the guide element 16'. By contrast with 
the first embodiment, therefore, in this embodiment the side walls 18' and 
19' can be spaced somewhat from the periphery of the upper roller 7. 
In a third embodiment shown in FIGS. 6-9, the drafting assembly 27 has 
generally the configuration of the embodiment of FIG. 1 although here the 
running surface of the lower roller 3" has a slightly greater diameter 
than that of its shaft 28. The lateral guide element 29 is in this 
embodiment somewhat differently shaped and arranged. 
The side walls 30 and 31 are formed as rings with cutouts while the web 32 
is in the form of a cylindrical segment. The web 32 is disposed to the 
right, i.e. the rear, of the lower roller 32" (see FIG. 6) while side 
walls 30 and 30 flank the edges 20 and 21 of the lower belt. The rings 30 
and 31, moreover, overlap the flanks 33 and 34 of the running surface of 
the lower roller 3". Because the flanks of the lower roller prevent 
shifting of the element 29 and the side walls 30, 31 in turn prevent 
lateral shifting of the belt 10, the latter is guided between the rings 30 
and 31 safely. The stationary rail 15' reaches into the cutouts of the 
rings to prevent rotation of the guide element 29. 
When flanks 33 and 34 are not provided, i.e. the roller is flush with its 
shaft 28, the rings 30 and 31 can extend sufficiently (FIG. 6) so that 
they can engage the flanks of the roller 7. The lateral guide element 29 
is likewise injection molded of a form-stable elastic synthetic resin in 
one piece and the cutouts can extend over less than half of the 
circumference of the rings so that the rings can be snapped over the shaft 
28. This simplifies mounting and dismounting of the lateral guide 
elements.