US2823705A - Lifting device for jack looms - Google Patents

Description

Feb. 18, 1958 H. .1. MICANDER LIFTING DEVICE FOR JACK LOOMS Filed March 2, 1954 IVENTOR. HERALD J-MIGAIVDER ATTORNEY.

United States Patent LIFTING DEVICE FOR JACK LOOMS Herald J. Micander, Redwood City, Calif. Application March 2, 1954, Serial No. 413,555

17 Claims. (Cl. 139-30) This invention relates to improvements in foot-power hand looms and, in particular, to an improved lifting device for a loom of the jack loom type wherein each heddle frame is capable of operation by a separate foot treadle.

Generally there are two types of foot-power looms suitable for home weaving. The operation of each depends on the foot action of treadles to raise or lower heddles carrying the warp threads so that a shed or opening may be formed for the passage of a manually moved shuttle carrying the weft threads. One of these looms is the counterbalanced loom which includes an overhead pulley and rope arrangement to support the customary harness frames carrying groups of heddles. With this type of loom the pulling down of one heddle carrying harness frame by a treadle acts to pull up a counterbalanced harness frame, thereby forming the shed. A chief difficulty with this type of loom, however, is the lack of flexibility resulting from the movement of two harness frames whenever a single treadle is depressed. A second type of hand loom is the jack loom, referred to above, where each harness frame is independently raised by some form of lever action connected to a treadle. The lifting action in the usual jack loom depends on a simple lever arrangement mounted above the harness frames with the amount of treadle pressure necessary to lift a harness frame equal to or greater than the weight of the frame.

in both the jack and counterbalanced loom, each lifting device is connected to an intermediate lever or lam which is pivotally connected at one end to the main loom frame. Each lam is then connected to a treadle. Consequently, in both types of looms the foot pressure required to lift each separate harness frame is not constant because each treadle is connected to a larn at a different point along its length. In a jack loom the variation in foot pressures required is even more marked due to the additional couplings between the separate lams and lever lifting devices. These couplings are generally uneven and often conflicting. In some cases the resulting lever combinations require far greater treadle pressures than the weight of the harness frame and warp, resulting in uneven treadle response and a labored foot action for the weaver.

The problem of difficult foot operation is further complicated by a weight inertia inherent in a simple lever which must be initially overcome to start the pivot actions involved in the lever system. Consequently, the initial 3' foot pressure required to depress the treadle is considerably greater than the pressure necessary to continue the lifting action.

A further problem results from the requirement in present loom lifting devices of overhead supports for the various pulley or lever arrangements. These overhead supports not only constitute annoying obstructions which greatly increase the overall size of the loom, but usually requirefthe lifting attachment to the harness frames to be at the ends of theframes rather than at their centers of balance. Such an end atachment often prevents a truly vertical lifting motion of the harness frames in their guide frames, contributing further to an uneven or jerky heddle lifting action.

The present invention is directed to a solution to the above and many additional problems by the provision of an improved heddle lifting device for a jack type loom. Consequently, one object of the present invention is to construct each lifting device as a parallel bar expansion means, in which both the lam and harness frame are parallel bars, so that a lazy tong lifting action will be performed on each heddle at the first treadle pressure. In this way treadle response will be uniform for each lifting action, permitting an even, unlabored foot action by the weaver.

Another object of the present invention is to provide such a lifting device in which the lifting force may be applied to each harness frame at a single point adjacent its center of balance so that a truly vertical lifting motion will result.

Another object is to provide such a lifting device in which the lam is not pivoted to the frame, but forms a parallel part of the lifting device so that a foot treadle may be connected to the lam at any point along its length without interfering with the parallel, upwardly expand ing effect of the lifting device.

Another object is to construct each lifting device as a compound lever expansion means, positioned beneath the harness frames, so that overhead levers and pulleys may be eliminated to provide a lower, better designed loom.

Another object is to produce a very simple, compact, trouble-free heddle lifting action for foot-powered hand looms, that is more free from friction than most loomlifting systems.

Other objects and advantages of the present invention will appear from the following description of a preferred embodiment and from the drawings in which:

Fig. l is a perspective view of the essential features of a number of heddle lifting devices according to the present invention, showing the manner in which they might be used to interconnect the heddles, harness frames, and foot-actuated treadles of a foot-powered hand loom;

Fig. 2 is a view in side elevation, on an enlarged scale, of a single lifting device indicating the manner in which it might be connected between a foot treadle and harness frame;

Fig. 3 is a view in vertical section on the line 33 of Fig. 2 of a particular detail of the harness frame connection of Figs. 1 and 2, with parts in elevation; and

Fig. 4 is a view in side elevation of a modified arrangement of a pivot support for the lifting device of the present invention.

Referring to the drawings generally,

The letter A indicates the conventional harness frames of a foot-powered hand loom, which are adapted to slide in the grooves 6 in a pair of vertical supports S that form part of the main loom frame (not shown). Supported in the harness frames A by transverse bars 7 are the usual heddles 8 which have openings 9 intermediate their ends to receive the warp (not shown). Pivoted on a lower portion of the loom frame by a pivot rod 10 are foot treadles B which are connected to lams C by the usual cords or wires 11. Connecting each harness frame A to its respective lam C is a lifting device D, constructed according to the present invention, which operates to lift a harness frame and its warp threads vertically each time its corresponding treadle B is depressed. As shown in Fig. 1, the left hand treadle B has been depressed, causing the rear harness frame A to move vertically in its slide frame.

Each lifting device D is supported'in the main loom frame by a pair of shafts 12 having their ends secured in frame cross beams 13. Preferably the shafts 12 are so positioned that they lie in a single horizontal plane. The two shafts 12 constitute bearing points for each of the lifting devices from which they expand in a vertical direction upon actuation by a foot treadle B, as will be later described in detail.

The bearing support for the lifting devices is best illustrated in Fig. 2 where the structure of a single lifting device is disclosed. As shown, there are two main levers 14 which are pivotally connected intermediate their ends by a central pivot 15. Spaced an equal distance from the central pivot 15 on upper lever arm portions 16 are pivoted bearing arms 17. These bearing arms 17 are pivoted on the support shafts 12 to provide a swinging pivotal support for each lifting device D.

Pivotally secured to the extending ends of the upper arm portions 16 of the main levers are secondary levers 18 which are connected at their upper ends by a common pivot 19. A harness frame connecting pin 20 is also secured to the upper pivot 19, connecting a harness frame A to the lifting device for pivoted motion. This harness frame connection may be provided by inserting the pin 20 into a bore 21 in the lower wooden bar or shaft 22 of the harness frame A. Fig. 3 illustrates a construction for the harness frame connection which is designed to maintain .the harness frame A in a parallel relationship with the lifting device D. As shown, this connection may be simply a metal ferrule 28 driven into the shaft 22 to receive a forked end portion of the pin 20. The forked construction of the pin 20 permits the pin slot 29 to be opened slightly to insure a snug fit in the ferrule 28 and also to permit compensation for wear. However, any

other suitable connection for the purpose may be provided.

The lam C is pivotally hinged to the lifting device D by links 23. The upper ends of the links 23 are pivoted in lower arm portions 24 of the main levers 14, while the lower ends of the links are similarly pivoted at 25, adjacent the ends of the lam C. Preferably, the links 23 are received in recessed grooves 26 in the ends of the lam to insure a free swinging action of the lifting device with respect to the lam. The lam C is provided with a series of conventional apertures 27 to receive the cords 11 by which each lam is connected to a foot treadle B.

The operation of the lifting device of Fig. 2 is as follows: When the treadle B is depressed with foot pressure, the cord 11 pulls the lam B down. The links 23 swing inwardly about their pivots into the position shown, permitting the lower arm portions 24 and the main lever to move together about the pivot 15. The pivot bearing arms 17 also permit the upper lever arm portions 16 to move together in a similar fashion. This closing movement of the upper arm portions 16 of the main levers 14 causes the common pivot 19 adjacent the harness frame connection to move in an upward lifting thrust, raising the harness frame A.

When the foot pressure is removed from the treadle B, the weight of the harness frame pushing down on the upper pivot 19 will cause the extended upper lever portions 16 to move apart, resulting in a corresponding movement of the lower main lever arm portions 24. The ultimate effect will be a decrease in the vertical dimension of the lifting device, causing the lam C to move the treadle B upwardly to its normal position.

The action of the lifting device D may best be described as a type of lazy tong compound lever action which causes the device to expand or contract about the two bearing or support points provided by the shafts 12. Thus when the foot pedal is depressed, the lifting device expands upwardly from the bearing points at 12. Because of the scissors action inherent in the lazy tong movement, the lifting effect begins at the first treadle pressure, tending to overcome the inertia that is encountered in a simple lever action.

It will ,beobserved from the description abovethat th Combined structures of a harness frame A, lifting dVi D, and lam C constitute a form of parallel bar expansion means in which the frame A and lam C both constitute parallel bars. This parallel action is possible because the swinging hinge action of the links 23 permits the lam C to remain horizontal throughout the compound lever actions involved in vertical expansion of the lifting device, While the suspension of the lifting device on the two hori' zontal support shafts 12 insures a perpendicular thrust through the lazy tong or scissors action of the lever arms 14 and 18. As a result, the thrust of the lifting device D may be applied at the center of balance of a harness frame A, through the connecting pin 20, permitting a truly vertical sliding motion of the harness frame A in its guide grooves 6.

As a result of this unique coaction of leverages into a parallel expansion unit, the weight inertia losses inherent in the conflicting lever couplings of the prior art are substantially eliminated. A primary reason for the improvement is the elimination of any pivoted connection between the lam C and the main frame by the provision of a freely movable lam suspended with the lifting mechanism from two bearing points on the horizontal shafts 12.

A further advantage of having each lam freely suspended in a horizontal plane is the uniformity of treadle pressures possible on the various treadles B. This uniformity is possible because the action of a lam C no longer depends on a pivoted motion about a fixed pivot on the frame but, instead, each lam becomes a part of the lazy tong action of a lifting device, and acts as a horizontal stabilizing bar. As a result, a foot treadle may be connected to the lam at any point along its length without substantial variation in the downward treadle pressure required and without interfering with the parallel, up- Wardly expanding action of the lifting device. The ultimate effect is that each treadle B will respond uniformly to equal treadle pressures, permitting any harness frame A to be cleanly and smoothly raised in an unlabored weaving action.

A further feature of the new lifting action is the direct transmission of treadle pressure through the compound lazy tong lever action to a harness frame A. This not only permits the equal treadle pressures referred to above, but also eliminates the necessity of treadle pressures greater than the weight of an individual harness frame. Thus, contrary to the prior art, equal pressures on each treadle will operate each lifting device and produce equal lifting forces on each harness frame A, thereby effectively counteracting the tendency toward unequal treadle response so prevalent in the prior art devices. Consequently, more uniform weaving as well as easy operation will result.

Finally, the fact that no portion of the heddle lifting mechanism need extend above the harness frames permits a much lower, more compact loom assembly. This feature is, of course, very desirable in a foot-power hand loom intended primarily for use in the home, and permits loom structures less than 40 inches in height. Smaller dimensions also are important when it is desired to move the device in the home or to transport it to distant locations.

To those skilled in the art to which this invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the invention. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting. For example, the pivoted bearing arms 17 could extend downwardly from their pivotal connection to the main lever arms 14 and still provide the desired pivoted support. Such a modified arrangement is illustrated in Fig. 4.

What I claim is:

1. An improved harness-frame lifting device for footpower hand looms comprising a pair of fixed shafts mounted in a main frame, a pair of main lever arms crossing each other and pivotally connected to each other and each pivotally supported on one of said shafts, a pair of secondary lever arms, each pivoted on an extending end of a main lever arm and having a common pivotal connection, said common pivotal connection constituting a single pivotal connection between a harness frame and said lifting device, whereby said harness frame may be supported on said lifting device at its center of balance, thereby permitting a truly vertical lifting action. 2. The device of claim 1 wherein each of said main lever arms has a pivotal connection to a link which is in turn pivotally connected to a lam connected to a treadle, whereby said lam and said harness frame constitute parallel members of a parallel bar expansion means permitting the latter to respond easily and instantaneously to foot actuation of said treadle.

3. In combination with a foot-power hand loom of the jack loom type including a main frame, foot treadles, lams, heddles, harness frames and lifting devices connecting the lams to the harness frames, the improvement in an individual lifting device of a pair of main levers having a common pivot axis positioned intermediate extending arm portions and a spaced-apart dual pivoted support on said frame, secondary levers having pivotal connections to upper extending arm portions of said main levers and a common pivotal connection to a harness frame, and pivotal connections between lower extending arm portions of said main levers and an adjacent lam, whereby each of said lifting devices comprises a compound expanding linkage between a lam and harness frame operable by a treadle pressure that is uniform for each of said lifting devices.

4. An improved harness-frame lifting device for footpower hand looms of the jack type comprising a frame, a combined parallel bar and lazy tongs expansion means supported on a pair of horizontal pivot shafts mounted in the frame, said expansion means having a single pivotal connection to a harness frame and two spacedapart pivots connecting the same to a treadle-actuated lam, whereby said 1am may act as a stabilizing bar for said lifting device since said treadle may be connected to the lam at any point along its length without interfering with the parallel upwardly expanding effect of the lifting device.

5. The device of claim 4 wherein said harness frame and said lam constitute parallel portions of said parallel bar expansion means whereby a truly vertical thrust is exerted by said lifting means on said harness frame.

6. The device of claim 4 wherein a plurality of said linkages is supported on said horizontal shafts, with each linkage interconnecting a treadle-actuated lam and a harness frame, whereby each lifting device may be actuated by substantially the same foot pressure.

7. A foot-power hand loom of the jack-loom type, including in combination: a main frame; a pair of bearing shafts supported by said main frame; a plurality of foot treadles a corresponding plurality of lams connected to said foot treadles; a corresponding plurality of heddlesupporting harness frames; and a corresponding plurality of expansion means connecting each said harness frame to one lam and holding each lam and its harness frame parallel to each other at all times, each said expansion means comprising lazy-tongs having a pair of crossing main levers pivoted together intermediate extending arm portions, one of said arm portions being pivotally linked to a lam, and each pivoted on one bearing shaft, and a pair of secondary levers pivoted to each other and to a harness frame at one end and at their other ends each pivoted to one said main lever adjacent the ends on the opposite sides of said bearing shaft from said lam.

8. A foot-power hand loom of the jack-loom type, in cluding in combination: a main frame; a pair of fixed bearing shafts supported by said main frame; a plurality of foot treadles pivotally mounted on said main frame; a corresponding plurality of lams connected to the outboard end of said foot treadles; a corresponding plurality of heddle-supporting harness frames; and a corresponding plurality of expansion means connecting each said harness frame to one lam and holding each lam and its harness frame parallel to each other at all times, all said expansion means being pivotally mounted on both of said bearing shafts, each said expansion means comprising lazy-tongs having a pair of crossing main levers pivoted together at their crossing intermediate extending arm portions, a link joining the end of one said arm portion of each lever to one end of a lam, said link being pivotally connected to said lam and to said arm portion, a link pivotally mounted on one said bearing shaft and pivotally attached to and joining the other arm portion of each main lever intermediate its end and said crossing, and a pair of secondary levers pivotally joined to each other and to a link rigidly attached to the harness frame at a common point at one end of each said secondary lever, said secondary levers being pivoted at their other ends to said main levers adjacent the ends of the arm portion on the opposite side of said bearing shafts from said lam.

9. In combination with a foot-power hand loom .of the jack-loom type including a main frame, foot treadles, lams, heddles, harness frames, and lifting devices connecting the lams to the harness frames, the improvement in an individual lifting device of a pair of crossing main levers having a common pivot axis positioned intermediate extending arm portions above and below said com-' mon pivot, links pivoted intermediate said common pivot and the ends of the upper arm portions, said links providing a spaced-apart dual pivoted support on said frame for said lifting device, secondary levers having pivotal connections adjacent the ends of said upper arm portions and a common pivotal connection to a harness frame, and links pivotally connected at one end to the lower arm portions of said main levers and at their other end to an adjacent lam, whereby each of said lifting devices comprises a compound expanding linkage between a lam and harness frame operable by a treadle pressure that is uniform for each of said lifting devices.

10. In combination with a foot-power hand loom of the jack loom type including a main frame, foot treadles, lams, heddles, harness frames, and lifting devices connecting the lams to the harness frames, the improvement in an individual lifting device of a pair of pivotally crossing main levers having a spaced-apart dual pivoted support on said frame, secondary levers having pivotal connections to the upper ends of said main levers and a common pivotal connection to a harness frame, and pivotal connections between the lower ends of said main levers and an adjacent lam, so that each said lifting device provides a lazy-tongs linkage between a lam and harness frame operable by uniform treadle pressure.

11. An improved harness-frame lifting device for footpower hand looms comprising a parallel bar expansion means in which a harness frame constitutes one parallel member and a lam constitutes another, a pair of first lever means crossing each other and pivotally attached to each other where they cross, having spaced-apart inner ends pivotally secured to said lam and outer ends, a pair of second lever means each pivotally secured. at one end to a said outer end of said first lever means and each pivotally connected to said harness frame, said first and second lever means constituting a lazy tongs, whereby an easy, substantially inertia-free working action is imparted to the lifting device through a lazy-tong lever action.

12. The device of claim 11 in which said harness frame engages said second lever means at a single pivot point adjacent the frames center of balance and along the center line of said lazy tongs, so that a truly vertical thrust may be imparted to the harness frame.

13. The device of claim 11 in which the pivotal com nections of said first lever means to said lam lie adjacent its ends and in which a foot treadle is connected to the "7 lam, the connection being at any point along its length without interfering with the parallel upwardly expanding effect of the lifting device.

-14. An improved harness-frame lifting device for hand looms comprising a main frame, a plurality of treadles pivoted on the main frame, lams connected to each of said treadles, andcompound expanding lever means interconnecting each 'lam with a heddle-supporting harness frame, each of said lever means having a pair of lever arms pivotally crossing each other and having pivotal connections adjacent one end with an adjacent lam, and pivotally connected at the other end to second lever means that'are pivotally connected to a said harness frame, whereby .on depressing a treadle and its connected lam one of said harness frames will be raised by a lever means.

15. The device of claim 14 wherein a pair of fixed shafts supported by said main frame pivotally support all said expanding lever means, said shafts being in a single horizontal plane so that a truly vertical thrust is imparted to a harness frame on actuation of its interconnecting lever means.

16. An improved harness-frame lifting device for footpower hand looms comprising a lam connected to a foot treadle pivotally mounted on a main frame, a heddle-supporting harness-frame slidably mounted in the main frame, a pair of bearing shafts mounted in main frame, and compound expanding lazy-tongs lever means pivotally mounted on said shafts below said harness frame and interconnecting said harness frame with said lam, said lever means including a pair of pivotally crossing arms, with one end of each secured pivotally to said lam and the other end pivotally secured to another of a pair of arms that in turn are pivotally connected to said harness frame, no portion of said lever means extending above said harness frame, whereby a relatively low loom structure may be provided.

17. An improved lifting device adapted to interconnect the lam and heddle-supporting harness frame structures of a foot-power hand loom comprising a compound expanding lazy-tongs lever system with a pair of pivotally crossing levers pivotally secured to said 1am at one end and at the other end pivotally secured to a succeeding pair of levers which have a single connection to a harness frame at its approximate center of balance, whereby an even lifting motion is easily imparted to said harness frame on actuation of said lifting device. I

References Cited in the file of this patent UNITED STATES PATENTS 2,240,061 Gilmore July 22, 1941 2,556,643 Booth June 12, 1951 2,576,428 Towle et a1 Nov. 27, 1951 2,696,838 Purrington Dec. 14, 1954

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