WO1999005349A1

WO1999005349A1 - Drive mechanism for a griffe frame

Info

Publication number: WO1999005349A1
Application number: PCT/GB1998/002201
Authority: WO
Inventors: John Bertram Derrek Rush
Original assignee: Bonas Machine Company Limited
Priority date: 1997-07-23
Filing date: 1998-07-22
Publication date: 1999-02-04
Also published as: GB9815927D0; GB2327685A; GB9715480D0

Abstract

A drive mechanism for a griffe frame (12), the drive mechanism including at least one rotatable drive shaft (31) drivingly connected to at least one side of the griffe frame (12) via an eccentric assembly (32), the eccentric assembly (32) being adjustable to enable the amount of eccentricity to the eccentric assembly (32) to be selectively varied.

Description

DRIVE MECHANISM FOR A GRIFFE FRAME

The present invention relates to a drive mechanism for a griffe frame.

As is well known, a griffe frame is used in a Jacquard mechanism for raising/lowering hooks connected to healds and so move the healds between upper and lower shed positions.

The motion of the griffe frame is compound, viz it moves in a generally rectilinear manner between upper and lower shed positions and at the same time undergoes a rotary oscillatory motion.

It is generally desirable for the drive mechanism which drives the griffe frame to be independently adjustable in respect of the rectilinear motion and the rotary oscillatory motions.

It is also desirable for the drive mechanism to operate at high speeds.

A general aim of the present invention is to provide a drive mechanism which is capable of meeting the above criteria.

According to one aspect of the present invention there is provided a drive mechanism for a griffe frame, the drive mechanism including at least one rotatable drive shaft drivingly connected to at least one side of the griffe frame via an eccentric assembly, the eccentric assembly being adjustable to enable the amount of eccentricity to the eccentric assembly to be selectively varied.

Preferably the drive shaft is drivingly connected to opposite sides of the griffe frame by respective eccentric assemblies.

Preferably the or each griffe frame is drivingly connected to the drive mechanism at two spaced apart drive locations along each side. In one embodiment, the drive mechanism includes two drive shafts, each drive shaft being arranged to drive a respective drive location. In another embodiment, the drive mechanism includes a single drive shaft which is arranged to drive both drive locations.

Preferably the or each drive shaft is continuously rotated in the same direction. Alternatively, if desired, the or each drive shaft may be oscillated in opposite rotary directions through a predetermined arc.

In a further embodiment, each eccentric assembly is drivingly connected to the griffe frame via a slide assembly.

In an alternative embodiment, each eccentric assembly is rotatably connected to a connecting rod which in turn is pivotally connected to the griffe frame.

Various aspects of the present invention are hereinafter described with reference to the accompanying drawings, in which: -

Figure 1 is a schematic side view of a griffe frame driven by a drive mechanism according to a first embodiment of the present invention; Figure 2 is a more detailed part side view of the mechanism shown in

Figure 1;

Figure 3 is a sectional view along line III-III in Figure 2;

Figure 4 is a view similar to that shown in Figure 2 showing a second embodiment according to the present invention;

Figure 5 is a sectional view along line V-V in Figure 4;

Figure 6 is a side view of a griffe frame driven by a drive mechamsm according to a third embodiment of the present invention; Figure 7 is a part side view similar to Figure 6 showing part of a griffe frame driven by a fourth embodiment according to the present invention.

Figure 8 is a schematic side view of a griffe frame driven by a drive mechanism according to a fifth embodiment of the present invention.

Referring initially to Figure 1 there is shown a griffe frame 12 from which a plurality of knives 14 are suspended. The knives 14 are connected to opposite sides 12a (only one of which is visible) of the griffe frame via links 16 which are pivotally attached to the respective side 12a at locations 18.

If desired, the knives 14 may be fixedly secured to the opposite sides

12a in a conventional manner.

As shown schematically in Figure 1 , the griffe frame 12 is constrained by suitable guides (not shown) against lateral movement (as indicated by arrow L) such that when the griffe frame 12 is raised and lowered, it undergoes a substantially rectilinear movement as indicated by arrows SH. Such movement in direction SH determines the shed height between upper and lower shed positions.

As indicated by arrows SI, the griffe frame 12 undergoes a rotary oscillatory motion about pivot axis P as it reciprocates between upper shed and lower shed positions. The degree of this rotary oscillatory motion determines the amount of shed inclination at either the upper shed and/or lower shed position.

In the embodiment shown in Figure 1, the griffe frame 12 is driven between its upper and lower shed positions by a drive mechanism 30. The drive mechanism 30 includes a pair of drive shafts 31 each of which is drivingly connected to side 12a of the griffe frame 12 by an eccentric assembly

32.

Each drive shaft 31 preferably extends across the width of the griffe frame and is drivingly connected to the opposite griffe frame side (not shown) by an eccentric assembly 32.

Each eccentric assembly 32 is preferably constructed so that its amount of eccentricity is adjustable, preferably in discrete increments.

By adjusting the degree of eccentricity of the assemblies on both shafts 31, it is possible to adjust the displacement of the griffe frame in the direction of arrows SH and also in the direction of arrows SI independently of one another. Adjustment in the direction of arrow SH is achieved by adjusting the amount of eccentricity of each eccentric assembly, and the adjustment in direction of arrows SI is achieved by adjusting the amount of difference between me eccentricities of the eccentric assemblies.

In Figures 2 and 3 the eccentric assembly 32 is shown in more detail.

The assembly 32 includes a collar 40 which is fixedly secured on the drive shaft 31 , preferably by being heat shrunk onto it. The collar 40 is formed with an eccentric portion 41 which is eccentric relative to the axis of the drive shaft 31 , the portion 41 defining a first eccentric of the assembly 32.

A second eccentric 45 is mounted on the first eccentric. The second eccentric 45 is in the form of an annular disc having an inner cylindrical face 47 and an outer cylindrical face 48.

The cylindrical faces 47, 48 are eccentric relative to one another. Accordingly, rotation of the first and second eccentrics relative to one another alters the degree of eccentricity of cylindrical face 48 relative to the axis of shaft 31. The first and second eccentrics are retained in desired rotary positions relative to one another by locking means 170.

The cylindrical face 48 is used to drivingly displace the griffe frame and so adjustment of the relative rotary position of the first and second eccentrics can be utilised to adjust the amount of displacement of the griffe frame on rotation of each shaft 31. By way of example, a range of adjustment may be implemented by providing for adjustment between subtraction of the two eccentricities through to addition of the two eccentricities. For example, the range required might commonly be from 50 mm to 130 mm of vertical movement of the griffe frame. The mean of these two extremes is 90 mm and the adjustment required is then plus or minus 40 mm. In terms of eccentrics which are arranged to directly drive the griffe frame, this range of displacement of the griffe frame would be provided by an eccentric with an eccentricity of 45 mm (ie. 90 mm throw or displacement), in combination with a second eccentric with an eccentricity of 20 mm (40 mm throw). The eccentricity of 25 mm (ie. providing the lower limit displacement of 50 mm) can be provided by opposing the inner and outer eccentrics, (such that their eccentricities are subtracted, viz. 45-20 mm), and the eccentricity of 65 mm (ie. providing the upper limit displacement 130 mm) can be provided by aligning the two eccentrics, (such that their eccentricities are added, viz. 45 + 20 = 65 mm).

In the embodiment illustrated in Figures 2 and 3 a bearing 50, preferably a ball bearing assembly having inner and outer races, is mounted on the cylindrical surface 48. A drive collar 51 is mounted on the bearing 50 so as to be rotatable relative to the second eccentric 45.

The drive collar 51 is constrained to run between a pair of opposed rails 56, 57 which are fixedly secured to the griffe frame side 12a.

Preferably the collar 51 directly contacts rail 56 and indirectly contacts rail 57 via a carriage 60. The collar 51 , rails 56, 57 and carriage 60 are adapted to co-operate to resist relative lateral displacement therebetween in the direction of rotation of the shaft 31. In this respect, collar 51 is preferably provided with inclined faces 65 which define a centrally located ridge extending about the outer periphery of the collar 51. Rail 56 is provided with corresponding inclined faces 66 which define a V-shaped channel for receiving the ridge of the collar.

The carriage 60 preferably includes a support frame 61 on which a pair of wheels 63 are rotatably supported.

Each wheel 63 preferably has a V-shaped peripheral groove to receive the ridge of the collar 51. Accordingly, rail 57 is provided with inclined faces defining a V-shaped ridge extending therealong on which the wheels 63 ride.

In operation, as shaft 31 rotates the collar 60 is driven by the eccentric assembly to reciprocate along rails 56, 57 and at the time cause the griffe frame to rise and fall.

Preferably each wheel 63 includes two wheel halves 63a, 63b which are resiliently biased in an axial direction toward one another. Accordingly, differences in the distance between rails 56, 57 may be accommodated as the carriage 60 reciprocates along rails 56, 57 by the wheel halves 63a, 63b moving axially apart/together.

Preferably the locking means 270 of the assembly 32 is adapted to enable adjustment of the eccentricity to be achieved in discrete increments. In this respect the second eccentric is provided with a series of through bores 74 through which bolts 73 may pass.

The collar 40 is provided with a pair of diametrically opposed (relative to eccentric portion 41) threaded bores 75 into which bolts 73 may be threadedly received.

The series of bores 74 are arranged in diametric pairs such that by rotating the second eccentric relative to the first eccentric, a selected pair of bores 74 may be aligned with thread bores 75. Bolts 73 are then passed through these aligned bores and tightened. The collar 40 is provided with an accurately machined axially facing shoulder 40a against which the second eccentric abuts when bolts 73 are tightened. This ensures accurate alignment of the first and second eccentrics after adjustment. In order to ensure that loadings are accommodated, wedge means 170 are provided to remove radial play between the first and second eccentrics. Accordingly, the second eccentric preferably includes a wedge collar 70 via which the second eccentric is mounted on me first eccentric. To tighten the wedge collar 70, a lock plate 71 is provided overlying the second eccentric and bolts 72 are fed through me plate 71 to be threadedly received in the wedge collar 70. Accordingly, tightening of bolts 72 causes the collar 70 to be drawn toward plate 70 and thereby wedging connects the first and second eccentrics and removes radial play therebetween.

In the embodiment 100 shown in Figures 4 and 5 similar parts have been designated by the same reference numerals.

Embodiment 100 differs in that me sliding drive to the griffe frame 12 is achieved via a sliding block 101 which is slidingly received on opposed rails 56, 57. In embodiment 100 sliding block 101 replaces die drive collar 51.

In the embodiment 200 shown in Figure 6, a pair of eccentric assemblies 32 are provided which drive the griffe frame 12 via a connecting arm 210.

Each connecting arm 210 is pivotally attached to the griffe frame 12 preferably by a bearing assembly 211. Preferably the point of attachment of the arm 210 to the griffe frame 12 is adjustable to provide an adjustment facility in addition to that provided by the eccentric assemblies 32.

Preferably as shown in Figure 6, a long link arm 220 is provided which is pivotally attached at one end to the static frame 215 of the jacquard machine and at its other end to the griffe frame 12 at a position substantially co-incident with pivot point P (Figure 1).

Use of a sufficient long arm 220 constrains the griffe frame 12 to rise and fall in a substantially rectilinear manner.

An alternative embodiment 300 is illustrated in Figure 7 wherein the connecting arms 210 are defined by a pair of threaded rods 310 which carry a boss 320 which is pivotally connected to the griffe frame 12. The boss 320 may be moved toward and away from the eccentric assembly 32 by adjustment of nuts 325 and so provide additional adjustment.

A fifth embodiment 400 is illustrated in figure 8 wherein a single drive shaft is provided for driving the griffe frame.

In the embodiment 400 shown in figure 8 similar parts to those described in the previous embodiments have been designated by the same reference numerals.

In embodiment 400, the griffe frame 12 is suspended from a pair of links

410. One end of each link 410 is pivotally attached to the griffe frame 12 and the opposite end of each link 410 is pivotally attached to a respective bell crank lever 412. Each bell crank lever 412 is pivotally mounted on a support frame (not shown) via a pivot connection 414.

Each bell crank lever 412 is pivotally connected to a respective push rod 416 by a pivot connection 418. Each push rod 416 is rotatably connected to a common drive shaft 31 via a respective eccentric assembly 32. Accordingly rotation of the shaft 31, causes each eccentric assembly 32 to reciprocate its associated push rod 416 by a pre-selected amount and hereby cause me griffe frame to be raised/lowered via the bell crank lever 412 and link 410 connections.

It will be appreciated that by appropriate adjustment of each eccentric it is possible to adjust the inclination of the griffe frame 12 at its upper and/or lower shed positions and also the height displacement of the griffe frame between its upper and lower shed positions.

In Figure 8, the mechanism is illustrated having a second pair of links 410a connected to the respective bell crank levers 412, the links 410a being connected to a second griffe frame (not shown). Accordingly the single shaft 31 in embodiment 400 can be utilised to drive two griffe frames.

In the embodiments described above, the or each shaft 31 is preferably continuously rotated in one direction. However it is to be appreciated that if desired the or each shaft 31 may instead be rotated in an oscillatory manner through a predetermined arc equal to or less than 360°.

Claims

1. A drive mechamsm for a griffe frame, the drive mechanism including at least one rotatable drive shaft drivingly connected to at least one side of the griffe frame via an eccentric assembly, the eccentric assembly being adjustable to enable the amount of eccentricity to the eccentric assembly to be selectively varied.

2. A drive mechamsm according to Claim 1 wherein the drive mechanism is drivingly connected to the griffe frame at two spaced apart drive locations along one or both sides of me griffe frame via a pair of said eccentric assemblies.

3. A drive mechanism according to Claim 2 wherein a first of said pair of eccentric assemblies is driven by a first drive shaft and a second of said pair of eccentric assemblies is driven by a second drive shaft.

4. A drive mechanism according to Claim 2 wherein both eccentric assemblies of said pair of eccentric assemblies are commonly driven by the same drive shaft.

5. A drive mechanism according to any preceding claim wherein each eccentric assembly includes a first eccentric fixedly mounted on its associated drive shaft, a second eccentric mounted on the first eccentric, the second eccentric being drivingly connected to the griffe frame and being rotatably mounted on the first eccentric to enable the eccentricity of the eccentric assembly to be adjusted and locking means for retaining the first and second eccentrics at a desired rotary position relative to one another.

6. A drive mechanism according to Claim 5 wherein the locking means is arranged to retain the first and second eccentrics at discrete rotary positions relative to one another to thereby provide eccentricity adjustment of each eccentric assembly in discrete steps.

7. A drive mechanism according to Claim 5 or 6 wherein the first eccentric comprises a collar fixedly secured to said associated shaft, the collar having an eccentric portion upon which said second eccentric is rotatably mounted and having an axially facing shoulder against which said second eccentric abuts.

8. A drive mechanism according to Claim 7 wherein said locking means is arranged to clampingly abut said second eccentric against said shoulder.

9. A drive mechanism according to Claim 8 wherein said locking means includes a pair of screw-threaded bores formed in said shoulder and arranged diametrically opposite to one anomer about said eccentric portion, a series of pairs of diametrically opposed through bores formed in said second eccentric, each pair of diametrically opposed through bores being alignable with said pair of screw-threaded bores by relative rotation between said first and second eccentrics and a pair of screw-threaded bolts extending through a selected pair of diametrically opposed through bores and being screw-threadedly received in said pair of screw-threaded bores.

10. A drive mechanism according to Claim 7, 8 or 9 wherein said locking means further includes wedge means located inbetween die eccentric portion of the collar and said second eccentric, said wedge means being operable to wedgingly connect the first and second eccentrics to one another to remove radial play therebetween.