US3752194A

US3752194A - Loom shedding mechanism

Info

Publication number: US3752194A
Application number: US00230319A
Authority: US
Inventors: J Griffith
Original assignee: Bonas Machine Co Ltd
Current assignee: Bonas Machine Co Ltd
Priority date: 1972-02-29
Filing date: 1972-02-29
Publication date: 1973-08-14
Anticipated expiration: 1990-08-14

Abstract

A heald shaft operating means for a heald shaft of a loom whereby the shaft is operably associated with a pivotal lever arranged to be driven in one directional sense by the action of a cooperating cam means acting upon a follower carried by the lever, and in the opposed directional sense by the action of a compression spring operably associated with the pivotal lever.

Description

United States Patent Griffith Aug. 14, 1973 [54] LOOM SHEDDING MECHANISM 2,510,404 6/1950 Lake et a] 1. 9/82 3,230,983 l/l966 E 139/82 [75] Invent g g a Lmlewe" 2,263,678 11/1941 c s rnan 139/79 er y, ng an OTHER PUBLICATIONS [73] Assignee: Bonas Machine Company Limited,

Staffordshire Great Britain 2gO9247,g55 12-1970 German Application (Menegatto) [22] Filed: Feb. 29, 1972 [21] Appl. NOJ 230,319 Primary Examiner-James Kee Chi Attorney--James E. Nilles [52] US. Cl. 139/79, 139/57 57 ABSTRACT [51] Int. Cl D03d 5/00 1 [58] Field of Search 139/79, 78, 82, 88, A heal! Shaft Pemm8 means heald Shaft of a 89/57 55 32 80 loom whereby the shaft is operably associated with a pivotal lever arranged to be driven in one directional 56] References Cited sense by the action of a cooperating cam means acting upon a follower carried by the lever, and in the op- UNITED STATES PATENTS posed directional sense by the action of a compression gieneglzlitto 139/78 Spring operably associated with the pivotal level: i y laZZO a 3,l86,440 6/1965 League 139/88 4 Claims, 3 Drawing Figures Patented Aug. 14, 1973 2 Sheets-Sheet 1 Patented Aug. 14, 1973 3,752,194

2 Sheets-Sheet 2 LOOM SHEDDING MECHANISM This invention concerns narrow-fabric weaving looms, and in particular, though not exclusively, a shedding mechanism for such looms.

It is known in some loom constructions for heald shafts to be operated by levers which are held each in contact with the surface of a co-operating cam by means of tension springs located at or near to the extremity of the lever to which the heald shaft is connected. Such an arrangement, whilst being effective, has the disadvantage that the positioning of the spring is such that, in use its amplitude of movement will be relatively large and thus the springs to have a long operative life must be of sturdy construction, and thus comparatively heavy form and this leads to the creation of high inertia forces which tend to limit the speed of operation of the loom to a value lower than that which, in narrow fabric looms in particular, is desirable.

It is the object of the present invention to provide a shedding mechanism which will overcome or at least substantially mitigate the above outlined disadvantages and thus enable the loom to operate at the very high speed demanded by the present-day looms.

According to the present invention there is provided a loom shedding mechanism characterised in that the heald shaft is operably associated with a pivotal lever arranged to be driven in one directional sense by the action of a co-operating cam means acting upon a follower carried by the lever, and in the opposed directional sense by the action of a compression spring operably associated with the pivotal lever.

The invention will now be described further, by way of example only, with reference to the drawings accompanying the Provisional Specification, in which:

FIG. 1 is a schematic side elevation of a loom including a shedding mechanism according to one form of the invention.

FIG. 2 is a detail view on a larger scale of a second form of a loom shedding mechanism, and

FIG. 3 illustrates diagrammatically a heald frame and its manner of mounting in a loom.

Whilst the drawings and following description relate to a narrow fabric loom it is to be understood that the shedding mechanism may be applied to a loom of the kind used for weaving broad fabrics.

As shown in the drawings and in particular FIG. 3 there is provided a heald frame 10 whose vertically disposed elements 10a are constrained laterally by short guide blocks 13 mounted on slide elements 18 which guide the frame in its vertical movement. The slide elements 18 are mounted on the loom frame 14. The guide blocks 13 are, as shown located between upper and lower heald bars 15 and thus must be short enough to allow for unrestricted vertical movement of the heald frame 10 between upper and lower shed positions. A connecting rod 12 is rigidly attached at its upper end to heald frame 10 and pivotally connected in the transverse plane at its lower end to the extremity 16 of one arm 17 of a pivotal lever 17a. The connecting rod 12 has sufficient inherent flexibility to accommodate for the arcuate displacement of the lever extremity 16 when the loom is in use. The pivotal lever 17a has as its fulcrum a pivot shaft 11 and extending from this fulcrum in a direction opposite to arm 17 is a short arm 17b provided at its end with a cam follower 19 in the form of, for example a roller. The follower member 19 is caused as shown in FIG. 2, to make contact with the surface of a co-operating cam 20 mounted on a camshaft 21 journalled in the loom frame 14 and driven at an appropriate speed from the loom main shaft (not shown). The contact of follower 19 with cam 20 is maintained by use of a compression spring 22 acting on the arm 17 of pivotal lever 17a at close proximity to pivot shaft 11 (that is at a distance from the pivot shaft 11 no greater than the distance of the axis of the cam follower 19 from the pivot .shaft 11). Compression spring 22 is guided and provided with a re-action face by sheath block 24 mounted on the loom frame 14. A slidable piston 25 abuts the free end of the compression spring 22 and is provided with a push rod 26 having spherical formed ends 260 which are seated in mating spherical depressions 27 formed in both the piston 25 and the arm 17. Because of the close positioning of the cam follower l9 and compression spring 22 to the pivot shaft 11 the moment of inertia of the pivotal lever 17a about its fulcrum will thereby be kept to a low value, as will the bending moment which will be induced upon the arm 17 of the pivotal lever 17a only by the load derived from moving the heald frame mass and not by the force of the compression spring 21 and hence the proportions and thus the mass of this arm 17 can advantageously be somewhat less than is the case in known looms. Furthermore, the oscillations of the compression spring 22 will be of small amplitude due to the proximity of the spring to the fulcrum of lever 17a as will be the movement of the piston 25 and push rod 26 thereby keeping to a low value the inertia force deriving from these components and thus enabling very high operating speeds to be achieved.

As indicated in FIG. 1 the cam 20 may be replaced by a chain 28 the links of which are so formed as to produce a cam surface so that large pattern repeats can be achieved.

The invention is not restricted to the details set out above. For example, the dispostion of the follower l9 and spring 22 relative to the pivot shaft 11 can be altered to give the same effect; Details of such modifications will suggest themselves to persons skilled in the art of loom construction and thus it is not thought to be necessary to set these out in detail in this specification.

I claim:

1. A loom shedding mechanism comprising; a heald shaft; a lever pivotal about a fulcrum and operatively associated with said heald shaft; a follower carried by said lever; cam means cooperating with and acting upon said follower for driving said lever in one directional sense; a compression spring operatively associated with said lever for acting upon said lever in an opposed directional sense; the said follower and the said compression spring being positioned on opposite sides of said fulcrum with the compression spring in close proximity to the said fulcrum and a piston and push-rod assembly by means of which said compression spring acts upon said pivotal lever.

2. A loom shedding mechanism according to claim 1 including a cylinder in which said compression spring and said piston are mounted, said push rod extending between said piston and said lever.

3. A loom shedding mechanism as claimed in claim 1 in which the push rod is provided with partly spherical ends seated respectively in corresponding receiving formations in said piston and. said. lever.

that said heald frame is retained between said guide means throughout its entire range of movement; and guide blocks mounted upon said heald frame guide means between said spaced heald receiving bars for constraining said heald frame from lateral movement. i i IF

Claims

3. A loom shedding mechanism as claimed in claim 1 in which the push rod is provided with partly spherical ends seated respectively in corresponding receiving formations in said piston and said lever.

4. A loom shedding mechanism according to claim 1 wherein said heald shaft comprises: a movable heald frame having spaced heald receiving bars; a connecting rod connected to said lever and to said heald frame; a heald frame guide means to constrain said heald frame in a fore and aft direction and being of such dimensions that said heald frame is retained between said guide means throughout its entire range of movement; and guide blocks mounted upon said heald frame guide means between said spaced heald receiving bars for constraining said heald frame from lateral movement.