US3826155A

US3826155A - Lightweight lever for high mechanical stressing

Info

Publication number: US3826155A
Application number: US00358818A
Authority: US
Inventors: J Mueller
Original assignee: Sulzer AG
Current assignee: Sulzer AG
Priority date: 1972-05-12
Filing date: 1973-05-09
Publication date: 1974-07-30
Anticipated expiration: 1991-07-30
Also published as: DE2224285A1; JPS4947659A; FR2184613B1; JPS5238156B2; FR2184613A1; AT319154B; DE2224285B2; GB1371484A; CH553864A; DE2224285C3; CA1001052A; IT987286B

Abstract

The lever is constructed of a hub and a lever arm of composite structure which is secured to the hub. The lever arm is made of one or more strips of resin-impregnated carbon fibers cut from a board of like material. The boards are commercially prepolymerized to a predetermined extent. In addition, a loop of carbon fibers can also be used with the strips to form the lever arm. The arm is secured to the hub by a pressing and curing operation or is secured in place by an overlying cover.

Description

a we MM Miiller 4 July 50, 1974 [54] LIGHTWEIGHT LEVER FOR HIGH 2,18%,338 193g hNdoessinsger 133/145 MECHANICAL STRESSING 2,6 ,019 195 orris, r. 13 I57 n 2,655,949 /1953 Hagstrom 139/157 Inventor: Jochen Muller, Wmterthur. 2,777,472 1/1957 Pfarrwaller 139/145 Switzerland 2,990,725 7/l96l King 74/519 3,439,064 4 1969' M k k' 161 205 [731 Asslgnee Bmhm 3,551,272 12/1070 161/164 swltlerland 3,762,028 10/1973 Swearingen et al 156/306 [22] Filed: May 9, 1973 v Primary Examiner-Allan D. Herrmann [21] Appl' 3s8818 Attorney, Agent, or Firm-Kenyon & Kenyon Reilly Carr & Chapin [30] Foreign Application Priority Data May 12, 1972 Switzerland 007030/72 57 ABSTRACT 52 U.S. c1 74/519, 139/145 139/157 The lever is cwmu-cted hub and a lever arm of 156/309 161/196 403/261 composite structure which is secured to the hub. The [5]] Int CL 6058' 9 D0321 49/38 6091-5106 lever armvis made of one or more strips of resin- 5 Field of Search H 74 519. 1 1/196 213 1 4 impregnated carbon fibers cut from 3. board of like 161/205. 156/306 7 material. The boards are commercially prepolymer- 7 261 6 ized to a predetermined extent. ln addition, a loop of carbon fibers can also be used with the strips to form [56] References Cited the lever arm. The arm is secured to the hub by a pressing and curing operation or is secured in place by UNlTED STATES PATENTS an overlying Coven l,0l3,878 l/19l2 Hilton 74/548 X 1.902.569 3/1933 McDonald 21 Claims, 6 Drawing Figures OR IN 7 4/519 PATENTEB smamm snmzor 3 PATENTED JUL3 01974 I SHEET BM 5 LIGHTWEIGHT LEVER FOR HIGH MECHANICAL STRESSING This invention relates to a lightweight lever for high In this mechanism, a torsion bar has one end clamped so as not to rotate and the other end clamped to a hub of a picking lever. In addition, a picking stick is pivoted to or in the free end of the picking lever. In order to pick a shuttle, the torsion bar is twisted, and the energy stored in twisting is imparted to the picking lever at un twisting. The picking lever is thus able to act via the picking stick to shoot the shuttle through the shed at a particular speed. Weaving machine performance is determined, inter alia, by shuttle speed and picking rate, and so picking lever accelerations cannot but be very high. Since shuttle speed is determined by the energy stored in the torsion bar, the picking lever must be light to ensure that only some of such energy is consumed in stand heavy mechanical stressing. Another advantage is that the lever opens up further uses for a number of novel reinforcing fibers such as carbon fibers and boron fibers, which are the starting'materials for novel fiber composites of outstandingly good mechanical properties yet of very reduced weight. Difficult techniaccelerating the picking lever. Because of the high picking rate, the picking lever alos experiences very high alternate impact loads.

Picking levers can, of course, be made from highgrade steel, but are then heavy. Thus, a relatively large porportion of the torsion energy is consumed in accelerating the lever.

Accordingly, it is an object of the invention to provide a lever which is light in weight yet can withstand high mechanical stressing and can be made cheaply.

It is another object of the invention to provide alever which can be accelerated by a torsion bar without consuming large amounts of energy.

Briefly, the invention provides a lever having a hub including a pair of side walls defining a recess and a lever arm of composite structure received in the recess. The lever arm is made of at least one Prepreg strip and bears laterally on the side walls of the recess.

In one embodiment, the lever arm has a loop made of composite material which is received in the recess of the hub. in this case, the internal space of the loop is filled with at least on Prepreg strip; at least one end face of the loop is covered with at least one Prepregstrip; and the loop, the Prepreg strips and the hub are a secured together to form a pressing.

The term Prepreg is used to refer to a strip of material cut from a Prepreg" board which is a board made of resin-impregnated carbon fibers. The boards are commercially prepolymerized to a predetermined extent and are referred to as Prepregs" for short after the word Preimpregnated."

In another embodiment. the lever arm is removably received in the recess of the hub and a cover is removably secured, as by bolts, to the hub to secure the lever cal problems have to be solved in achieving the required constructional adaptation of the lever according to the invention to the special properties and requirements of the novel materials. Also, of course, the very high cost of the materials is an obstacle to their further development, since cost has so far restricted their use. A surprising feature is that the cost of the lever according to the invention, more particularly, when used as a picking lever in shuttle-type weaving machines, can be considered to be advantageous for industrial use.

The base of the recess in the lever according to the invention can beshaped to resemble a tongue which extends between the recess side walls in the direction of the lever arm. This feature provides a good connection between the hub and the lever arm. The lever can be formed with a pivot aperture embodied by a ring pressed together with the Prepreg strip and by an apertured disc on at least one side of the loop, so that the lever arm is reduced very little in the pivot aperture zone.

. The pressed-in apertured discs and the ring mean that there is substantially no weakening of the region around the pivot aperture in the lever arm.

Alternatively, the pivot aperture can be formed by an aperture in the Prepreg strips at an appropriate place.

Advantageously, the Prepreg strips are cut from a Prepreg board, and are laminated so that the reinforcing fibers in the various strips are oriented differently from one another, thus increasing the bending strength of the lever arm. Also, the strips on the sides of the lever arm can have different lengths, so that lever arm thickness decreases along the length of the lever arm. Advantageously, the loop is formed of resinimpregnated reinforcing fibers, to give a very solid core for the lever arm and a strong connection between the arm and the hub. Preferably, the apertured discs are made of resin-impregnated reinforcing fibers, such as carbon fibers, wound spirally.

In order to increase the strength of the transition between the hub and the loop, an adhesive means such as adhesive foils or sheets or the like can be provided between the hub and the loop.

. The lever of the invention is particularly useful as a picking lever in the picking mechanism of a shuttletype weaving machine.

These and other objects and advantages of the invention will become more apparent from the following detailed descirption and appended claims taken in conjunction with the accompanying drawings in which:

FIG. 1 illustrates an exploded view of the elements of I the lever according to theinvention;

arm in place. The advantage of this embodiment is that by removal of the cover.

diture of labor and, although light in weight, can with- FIG. 1a illustrates an inverted plan view of the hub of the lever of FIG. I;

FIG. 2 illustrates an alternative form of Prepreg strip;

FIG. 3 illustrates a plan view of the lever; FIG. 4a illustrates another embodiment of the lever according to the invention; and. FIG. 4b illustrates a front elevation of the lever of FIG. 4a with the cover removed.

Referring to FIG. 3, a picking lever for shuttletype weaving machines comprises a hub 1 which is made of steel or some other material and which has specially shaped portion 2 to connect the huh I to lever arm 3.

Referring to FIG. 1, the hub 1 has a clamping part 4 which cooperates with pins (not shown) which extend through passages 5 and 6 for clamping to a torsion bar of a picking mechanism. The shaped portion 2 of the hub 1 comprises a projecting part 7 having a pair of

side walls

11, and 12 and a base 9 defining a recess 8. Referring to FIG. 1a, the underside of the hub 1 is formed with a loop-shaped or U-shaped groove 10 of a depth such that the base 9 is absent in the region of

side walls

11, 12 and a central strip-like portion or tongue 13 remains between the

side walls

11, 12. A number of Prepreg strips 15-24 which partly resemble the shape of the finished picking lever shown in FIG. 3 are disposed one above another in laminated fashion on the underside of the lever.

The lengths of the strips 15-24 decrease towards the center of the layering, then increase away from the center. The difference in length leads to a tapering of the thickness of the picking lever in a decreasing manner along its length towards the free end. An apertured disc is positioned with an outside periphery 34 in abutment with one end 25 of strip 24. Two Prepreg strips 31, 32 are disposed on the strip 24 and have contoured ends, such as concave ends 33 which abut in mating relation with the outside periphery 34 of the disc 30.

In addition, an adhesive means such as an adhesive foil or sheet or the like 35, i.e., an adhesive in foil or strip or similar form whose curing cycle corresponds to the curing cycle of the Prepreg strips, is disposed on the strip 32. The function of the strip 35 is to reduce stresses in the adhesive layer during curing and during pressing of the lever as a result of differences between the coefficients of expansion of steel and carbon fibers.

A loop of a carbon fiber Prepreg is positioned on the strip 32 and foil strip 35 with the inside periphery 41 of a curvedend portion 42 of the loop 41 coinciding to some extent with the inside periphery 43 of the aperture in the disc 30. The opposite end of the loop 40 is disposed in the groove 10 (FIG. la) in.the underside of hub 1 and bears laterally on the

recess side walls

11, 12. The center of the curved end portion 42 and the center of the disc 30 are aligned with each other on. a straight line 44. An adhesive foil or sheet or the like 45 similar to the first such foil strip 35 is disposed on the loop 40 to lie between the tongue 13 and the loop 40.

A ring 46 is disposed in the curved end portion 42 of the loop 40 and the internal space 47 of the loop 40 is filled up with a number of Prepreg strips 50-55 having contoured, e.g. concave, ends 56 which abut the outside periphery 57 of the ring 46 in mating relation. The other end of the strips 50-55 extends as far as the front edge of the tongue 13 of huh I.

The inside space of the loop 40 is also occupied by relatively long Prepreg strips 58-67 whose ends 68 cover the hub tongue 13. The ends of strips 58-67 are also concave and are covered by an apertured disc 70 whose axis also lies on the straight line 44. The loop 40 is also covered by anumber of Prepreg strips -103 in which the first few strips 75-77 have concave ends abutting the outside periphery 106 of the disc while the next strips 78-99 decrease continuously in other than just specified.

length towards the outside. The difference in length also leads to a pressed picking lever whose thickness decreases along the length of the arm towards the free end. For the same purpose, the remaining strips 100-103 increase continuously in length.

In order to form the lever, the various components as shown in FIG. 1 are placed together in laminated form. Thereafter, when pressed at an appropriate pressure and temperature and for an appropriate time, all the components become integral together to form a pressing, due to the resins flowing together and being cured.

If the picking lever thickness is not required to decrease along the lever length, the strips 15-24 can be of the same length as one another, for instance, of the same length as the strip 15. Similar considerations apply to the strips 70-103, which can in this case, all be of the same length as the strip 70.

The thickness of the disc 30 corresponds approximately to the total height of the strips 15-24. The disc 30 can be wound by a known apparatus from a carbon fiber filament which has been resin-impregnated during winding. Alternatively, the disc 30 can be made of some other material, such as a metal or plastics, as can the disc 70. The ring 46 can also be made of a plastics or metal material.

The loop 40 too is wound by a known winder from a carbon fiber filament resin-impregnated during winding. The loop can also be wound from a Prepreg tape or band or the like.

The Prepreg strips are cut from a Prepreg board using a template so that the angle between the grain direction in the board and the longitudinal axis of the picking lever is alternately 0, 45 and 45 for the Prepreg strips. The grain angle for each Prepreg strip is indicated in FIG. 1 by short lines. For instance, the angle for the

strips

15, 16, 17 is 0,+45 and 45, respectively. The grain orientation can, however, be

The number of Prepreg strips 15 24 and IS-I03 is determined by the required thickness of the finished picking lever. The number of strips 50-67 in the interior 47 of the loop 40 is determined by loop height. For example, the strips 50-67 are provided in a number such that, after pressing, the entire interior of the loop 40 is filled with composite material. The strip shape depends upon the shape required for the finished picking lever, on the shape of the shaped portion 2 in the hub and on the shape of the loop 40.

The loop 40 need not necessarily have a covering of Prepreg strips on both sides. Depending upon strength considerations in the picking lever, it is, of course, possible to have just the strips 15-24 or just the strips 75-103 on one side.

Referring to FIG. 2, the Prepreg strips can be formed with an aperture 107 which serves as the pivot aperture 108 in the finished lever (FIG. 3). In this way, the

discs

30, 70 can be eliminated. The aperture 108 can, of course,- be formed by drilling the lever arm 3 after formation.

Composite materials containing carbon fibers have been mentioned in connection with the picking lever described, but other composite materials containing other reinforcing fibers, e.g. boron fibers, can, of course, be considered.

Instead of Prepreg strips, the picking lever can consist of discrete carbon fibers which are introduced into a press, used to make the lever, then impregnated with resin, and then joined together by wet pressing. This applies more particularly to the space 47 inside the loop 40. The lever can also be made with resinimpregnated whiskers instead of by individual fibers.

As noted above, the lever is not limited to use as a picking lever of shuttle-type weaving machines but can by used in other environments.

Referring to FIGS. 40 and 4b, the picking lever can alternatively comprise a hub 110 formed with a recess 111 having

side walls

112, 113 in which one rounded end 114 of a lever arm is received. As shown in FIG. 4b, the

side walls

112, 113 narrow toward the end to confine the matingly contoured arm 15. in addition, a cover 116 is secured by screws 130 to the hub 110 to retain the arm 15 in place.

The lever arm 115 is the same thickness over its whole length. Basically, the lever arm 115 is constructed like the lever arm shown in FIGS. 1 and 3. A loop 120 is made of a composite material with an internal space taken up by Prepreg strips. Laminations of Prepreg strips are also disposed on both

sides

121, 122 of the loop. A pivot aperture 123 is formed either by a ring 124 and apertured discs 125 or by the use of apertured Prepreg strips, for instance, of the kind shown in FIG. 2. The lever arm sides 126, 127 (FIG. 4a) abut the

recess side walls

112, 113, respectively.

The hub 110 is clamped by a clamping part 128 to a torsion bar 129 of a picking mechanism. After the screws 130 have been released, the lever arm 115 can be removed and replaced by another lever arm.

Instead of a lever arm which comprises a loop, a loopless lever arm can be provided. in this event, the lever consists just of one or more laminated Prepreg strips.

It is to be noted that the resin which is used in the Prepreg strips is of a nature to effect a good fibre to resin bond and, an integral bonding of the respective strips together and to the hub. An example of such a resin is an epoxy resin.

What is claimed is:

1. A lever of reduced mass for high mechanical stressing having a hub including a pair of side walls defining 'a recess,

and

a lever arm received in said recess in bearing engagement with said side walls and extending from said hub, said lever arm including a loop of composite material defining an internal space, at least one preimpregnated strip of material in said space and at least one preimpregnated strip of material covering one side face of said loop.

2. A lever as set forth in claim 1 wherein said loop and said strips are'integrally bonded to each other.

3. A lever as set forth in claim 1 wherein said hub includes an integral tongue between said side walls projecting into said space within said loop.

4. A lever as set forth in claim 1 further having a ring within said loop at one end of said lever arm and at least one apertured disc on one side of said loop aligned with said ring to define a pivot aperture.

5. A lever as set forth in claim 4 wherein each strip within said loop has an end contoured to abut said ring in mating relation and wherein said strip on said side face of said loop is contoured to abut said disc in mating relation.

6. A lever as set forth in claim 4 wherein said disc is formed of wound reinforcing fibers.

7. A lever as set forth in claim 6 wherein said fibers are carbon fibers.

8. A lever as set forth in claim 1 wherein said strips on said side face has an aperture at one end to define a pivot aperture.

9. A lever as set forth in claim 1 which includes a plurality of said strips, each strip having a graining oriented in angular relation to the graining of an adjacent strip.

10. A lever as set forth in claim 1 which includes a plurality of said strips on said side face of said loop, said plurality including strips of different lengths along said lever arm with the shorter strips being disposed be tween the longer of said strips and said loop.

11. A lever as set forth in claim 1 which further includes an adhesive means bonding said lever arm to said hub.

12. A lever as set forth in claim 1 1 wherein said adhesive means is an adhesive foil.

13. A lever as set forth in claim 1 wherein said loop is formed of wound reinforcing fibers.

14. A lever as set forth in claim 13 wherein said fibers are carbon fibers.

15. A lever as set forth in claim 1 which further has a cover secured to said hub over said lever arm to secure said lever arm in said recess of said hub.

16. A lever as set forth in claim 1 wherein said hub has a clamping portion for securing a bar therein, said clamping portion being disposed in perpendicular relation to said lever arm, and wherein said lever am includes a plurality of said strips within said loop each having a graining oriented in angular relation to the graining of an adjacent strip, and a plurality. of said strips on opposite side faces of said loop each having a graining oriented in angular relation to the graining of an adjacent strip, at least some of said latter strips being of different lengths to define a tapered lever arm.

17. A lever of reduced mass for high mechanical stressing having a hub including a pair of side walls defining a recess,

a lever arm received in said recess in bearing engagement with said side walls and extending from said hub, said lever arm including at least one preimpregnated strip of material, and

a cover secured to said hub to secure said lever arm in said recess of said hub.

18. A lever of reduced mass for high mechanical stressing having a hub including a recess, and

a lever arm secured in said recess, said lever arm including at least one strip of resin-impregnated carbon fibers and having an aperture at an end remote from said hub.

19. A lever as set forth in claim 18 wherein said lever is integrally bonded to said hub.

20. A lever as set forth in claim 19 which further has an adhesive means between said hub and said lever arm strip for reducing stresses during curing between said hub and said lever arm;

21. A lever as set forth in claim 18 wherein said lever arm has a loop at least partially engaged in said recess and wherein said lever further has a cover removably secured to said hub over said recess to removably secure saidlever arm in said recess of said hub.

Claims

1. A lever of reduced mass for high mechanical stressing having a hub including a pair of side walls defining a recess, and a lever arm received in said recess in bearing engagement with said side walls and extending from said hub, said lever arm including a loop of composite material defining an internal space, at least one preimpregnated strip of material in said space and at least one preimpregnated strip of material covering one side face of said loop.

2. A lever as set forth in claim 1 wherein said loop and said strips are integrally bonded to each other.

7. A lever as set forth in claim 6 wherein said fibers are carbon fibers.

10. A lever as set forth in claim 1 which includes a plurality of said strips on said side face of said loop, said plurality including strips of different lengths along said lever arm with the shorter strips being disposed between the longer of said strips and said loop.

12. A lever as set forth in claim 11 wherein said adhesive means is an adhesive foil.

14. A lever as set forth in claim 13 wherein said fibers are carbon fibers.

16. A lever as set forth in claim 1 wherein said hub has a clamping portion for securing a bar therein, said clamping portion being disposed in perpendicular relation to said lever arm, and wherein said lever arm includes a plurality of said strips within said loop each havinG a graining oriented in angular relation to the graining of an adjacent strip, and a plurality of said strips on opposite side faces of said loop each having a graining oriented in angular relation to the graining of an adjacent strip, at least some of said latter strips being of different lengths to define a tapered lever arm.

17. A lever of reduced mass for high mechanical stressing having a hub including a pair of side walls defining a recess, a lever arm received in said recess in bearing engagement with said side walls and extending from said hub, said lever arm including at least one preimpregnated strip of material, and a cover secured to said hub to secure said lever arm in said recess of said hub.

18. A lever of reduced mass for high mechanical stressing having a hub including a recess, and a lever arm secured in said recess, said lever arm including at least one strip of resin-impregnated carbon fibers and having an aperture at an end remote from said hub.

20. A lever as set forth in claim 19 which further has an adhesive means between said hub and said lever arm strip for reducing stresses during curing between said hub and said lever arm.

21. A lever as set forth in claim 18 wherein said lever arm has a loop at least partially engaged in said recess and wherein said lever further has a cover removably secured to said hub over said recess to removably secure said lever arm in said recess of said hub.