This invention relates to a top arm assembly for textile machine having modular loading means. The assembly also has looking means which is operable independently.
Textile spinning machines such as roving or ring spinning machines have a set of bottom rollers arranged in the spinning zone. A top arm having a similar set of rollers are provided at each location of the bottom rollers. The rollers of the top arm press against the corresponding bottom rollers when loaded thereby forming a drafting zone for the sliver or roving input. Drafting of the sliver or roving is influenced by the load of the top arm rollers on the bottom rollers. Conventional top arm has looking means for keeping the arm rigid in the loaded condition.
In conventional top arms locking and loading are effected by a thumb means which is pneumatically actuated. Loading and looking means in the known top arm arrangement consists of a thumb actuated by pneumatic means having a cam joint to the handle of the top arm. The thumb transmits its load to the handle and when the handle is locked with the top arm, the load is transmitted to the top arm for pressing the top arm rollers against the corresponding bottom rollers. The top arm and the thumb are fulcrumed on a fixed bracket to enable the above loading.

Since both these functions are effected by the same means, functional variation of one factor may result in manufacturing defects. For instance, defective locking would result in the variation of top roller load on the corresponding bottom rollers. Any manufacturing defect in any of the contributing components such as thumb, handle, load arm or fixed bracket may cause defective locking. It is also observed that roller diameter varies due to wear and tear leading to ineffective locking between the two sets of rollers. Yet another drawback noticed in the existing system is that any small variation of the components reflects considerably on effective loading. This is attributed to the relatively short distance between the levering elements such as the thumb and the handle or the handle and its fulcrum.
These drawbacks of the existing system can be avoided by
providing separate locking and loading mechanism in the top arm
assembly. Separating the loading function from the looking
function also increases the distance of pivoting point with
respect to both the loading and distribution points. This helps
in considerably reduction in load variations.
Our copending application no, 788/MAS/99 dated 3 August 1999 discloses a top arm assembly having independent locking and loading means.

The subject invention discloses yet another top arm assembly intended for overcoming the drawbacks and disadvantages of the existing top arm system. Pressure on the bottom rollers are applied through saddles. Loading function is achieved by horizontally mounted modules having spring means which can be adjusted. Spring loading is transmitted to the saddles through pressure thumbs. Loading brackets pivoted to the mounting means and disposed perpendicular thereto transmit the load to the saddle provided with a set of top rollers. Each modular loading means is located to relate to the corresponding bottom roller. The mounting and loading brackets are pivoted such that the distance between the thumb and the pivoting point and the distance between the pivoting point and the distribution point is equal so that the spring load produced is equal to the load desired.
The loading lever is pivoted to a support member and is kept rigid by engaging the locking lever with the fixed rocking cam in the support member. The top arm can be kept upright and unlocked by disengaging from the fixed cam and placing the lever on top of the cam.
Accordingly, the present invention provides a top arm
assembly for textile machines having modular loading means
comprising a support member having a loading lever provided with
at least one ' ""

horizontally disposed mounting means, each said mounting means having a spring actuated pressure thumb, an adjusting means and a loading bracket terminating in a saddle and top roller assembly and a locking lever movably disposed on a looking cam fixed on said support member.
This invention will now be described with reference to the Figure I in the accompanying drawings.
This figure shows the top arm assembly in the loaded and
locked position. The loading lever is indicated by numeral (1)
and the looking lever by numeral <2). The support member is
shown by numeral (6). The fixed locking cam is shown by (3) and
the looking roller for engaging and disengaging the locking lever
and the loading lever is shown by numeral (4). Mounting brackets
of the modular loading means is shown by numeral (7) and the
adjusting means, located on the spring to adjust the load is shown ^^
by numeral (8). The loading bracket and saddle are shown by reference numeral (9) and (12) while the pressure thumb is shown by numeral (II). A wear pad (10) is located between the loading bracket and the pressure thumb to avoid direct contact between them. The support frame is mounted on a guide tube indicated by reference numeral (5). The locking lever is operable independently of the loading lever.

Though the invention has been described hereinabove with a specific embodiment, obvious alterations known to persons skilled in the art are within its scope and that of the appended claims.

WE CLAIM :
1. A top arm assembly for textile spinning machines having
modular loading means comprising a support member (6) having a
loading lever (1) provided with atleast one horizontally disposed
mounting means (7>, each said mounting means having a spring
actuated pressure thumb (11) an adjusting means (8) and a
loading bracket (9) terminating in a saddle and top roller
assembly (12), and a locking lever (2) movably disposed on a
locking cam (3) fixed on said support member.
2. The top arm assembly as claimed in Claim 1, wherein the
support member is mounted on a guide tube.
3. The top arm assembly as claimed in Claims 1 and 2, wherein a
wear pad is provided between the pressure thumb and the loading
bracket.
4. A top arm assembly for textile spinning machines
substantially as described hereinabove and illustrated with
reference to the accompanying drawings.