US1061345A

US1061345A - Adjustable curve-scriber.

Info

Publication number: US1061345A
Application number: US6270?611A
Authority: US
Inventors: William S Weston
Original assignee: Individual
Current assignee: Individual
Publication date: 1913-05-13
Anticipated expiration: 1930-05-13

Description

W; S. WESTON ADJUSTABLE 0mm; SCRIBER.

AIPLIGA'UON TILED MAY .1 911,

Patented May 13, 191:5.

3 SHEETS-SHEET 2.

Witnesses: gy omamfw J v a ity f )2 a'iwm W. S. WESTON ADJ'YJSIABLE QURVE swam,

APPLICATION FILED MAY13. 19H

Patentai May 13, 1913.

flu/ent 47444421? 21 ,1 mZ y gggz UNITED 'sTATEs PATENT OFFICE.

WILL! 8. WESTON, 01' CHICAGO, ILLINOIS.

ADJUSTABLE crave-am 1,061,345. own-m a Letter: rum. Patented May s, 1913. Application fled Kay 18, 1811. lent-l Io. 7,086.

To all whom it m concern: arms are preferably rigid and arepivotally an enlarged scale. 3

Be it known that 1, WILLIAM a citizen of the United States, and a resident of Chicago, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Adjustable Curve- Scribers, of. which the following 18 a full, clear, and exact description.

The invention relates to adjustable curve 'scribers or rulers and more alticularly to adjustarble curves for use y draftsmen, model makers and the like for ruling regular curves of large radius.

e invention consists in the features of novelty hereinafter set forth, illustrated in different modified forms in the accompanying drawings and more particularly pointed out in the appended claims.

In the drawings, Figure 1 ls an edge view of one form of the im roved adjustable curve scriber or ruler wit a portion of the flexible ruling member broken awav. Fig. 2 is a plan view thereof with its flexible body in straight position. Fig. 3 1s a plan view with the flexible body curved for ruling a circular arc. Figs. 4, 5, 6 and 7 are sections on the lines 44, 5-5, 6-6 and 7-7, re-- spectively, ofFig. 3, Fig. 6 being shown on Figs. 8, 9 and 10 are views similar to Figs. 1, 2 and 3, showing another form of the improved curve scriber. Figs. 11 and 12 are detail sections on the lines 11--11 and 12-12, respectively, of Fig. 9. Fig. 13 is a view of the left-hand end of the ruler shown in Figs. 8, 9 and 10. Fig. 14 is a detail section of a part of the device on line 14-14 of Fig. 10. Fig. '15 is a partialiplan view of another form of the inven-, tion. Fig. 16 is a section on line 16-46 of Fig. 15 shown upon an enlarged scale. Figs. 17 and 18 are partial plan views of another modified form with the flexible body portion shown respectively in its straight and curved positions. Fig. 19 is a section on an enlarged scale on the lines 19-19 of Figs. 17 and 18.

T he improved adjustable curve scriber for ruling regular curves of large radius comprises a longitudinally extending flexible body which is referably formed of two or more members, one at least of which is a strip of steel or like resilient material, and a number of lever arms which are mounted upon the flexible body and maintained at fixed angles thereto. The longitudinal flexible body is provided with a ruling edge and the layer.

S. Wrsrou,

connected in pairs. The pairs of lever arms are preferably so arranged that the pairs of bases are formed by the common flexible body of the device. Suitable means are provided for moving-the points of mounting of the pairs of ipivoted arms tcgether aiid'apart along the xible body of the ruler to a greater or less extent and, inasmuch as the arms are held at fixed'anglas to the tlen'hle body, the latter is thereby bent into regular curves of varying radius.

In the form of the hvention Show a Figs. 1 to 7, inclusive, the longitudinal, flexible body of the ruler comprises two resilient bands 1 and 2 which are refienbly formed of thin sheet steel and a Kexihle'resihent member 3 formed of a strip of hard rubber, celluloid or the like. The resilient metal bands 1 and 2 are arranged edge to edge or in the same plane and slidabl engagethe ocves in the ugprer and ower portions 0 the flexible mom 3' and which grooves are pleferabl formed bya longitudinally extending shaped rib or fla 4 on the back of the ruling member. 11 this form, the two series of lever arms 5 and 6 project laterally from the upper and lower edges, respectively, of the flexible bands 1 and 2 and are preferably formed integral with these bands extending laterally therefrom substantially in planes at right angles to the planes of the bands. The two series of arms 5 and 6 which are thus connected respectively to the flexible resilient bands 1 and 2 are positel inclined and over lap, a s cleai'l showzl in Figs. 2 and 8. Beyond the T- aped rib 4 5 of one series is pivotally connected at its outer end to a companion arm 6 of the other series. These pivot connections may be of any suitable form, but in the prefen'edtorm illustrated, the arms are provided with enlarged circular and portions. 7 which are oppositely and outwardly dished or concaved and provided with openings for receiving the connecting pivots. In the form shown, these pivots com rise u p'er and" lower section's 8 and 9-whi eaten Ahmwa the openings of the circular end (irtions 7 of the arms and 6 and which pivot sec tions are provided with flange or shoulders that engage the outer faces of the cirdular end portions 7. Screws ll extend through the sect-ions of the pivots and secure them together with the shoulders 10 thereof engaging and pressed against the circular end portions 7. The outwardly concaved circular portions 7 are resilient and pressed outwardly against the shoal ders 10 of the pivot sections to take up the lost motion of the pivotal connections To facilitate the assembling of the parts and the tightening of the pivotal connec;

'tions, the outer portions of the pivot sections 8 and 9 are preferably hexagonal in shape, as shown, so that they may be engaged and held against rotation by wrenches. The arms 5 and 6 should be rigid, and for this purpose the main body portions thereof between the inner and outer ends are provided with longitudinal corrugations l2. Thefiexible memberfi is p eferably provided at its lower edge with anollsct shoulder 3' forming a convenient ruling edge. Th lowerfaces of this memher, of the arms 6 and of the lower pivot sections 9 are preferably all arrangedin the same horizontal plane so that the ruling device will properly engage a flat surface, as indicated by the line b---?) in Fig. 6. It is te observed, in this connection, that it is only preferable that the ruling edge shall be carried by the member or section 3 of the flexible body. In the construction illustrated, the'priinarv' function of the member 3 with its T-shaped rib 4 is to hold the bands 1 and 2 parallel. At the left-hand end of the rulin device (see Figs. 2, 3 and 5), he resilient nude 1 and are provided with laterally ofl'sot flanges 13 and l l, the flange 13,011 the upper band 1 merging with the endarm fih The flanges 13 and ll are bent together to contact along the medium plane a-a of the device and, the flange 13 is provided with a longitudinal slot 15,tbrough which extend a pair of screwslti. These screws extend through holes in the flange 14 and in two reinforclng pieces 17 which abut gainst the outer faces of the contactmg portions of the flanges A. similar slidln' connection between the bands is proed at th right-hand end of'the ruler in which the snort flan 14' is formed upon I 13 is formed upon the lower band 2 and mer is w'iththe', end arm 6' thereon. The

"flexi 1e: resilient bands are not only slidably connected at their ends, 4 but also "throughout their entire length by the flexi- 'ble member 3, so that th ey can shift rela- W tivelv ,to each other, but only in longitudiiial directidn. The two flexible members or gr es ane 2- m; held in diiierent adjusted positions by a clamp screw 18 which extends through the reinforcing ieces 17' at the righohand end of the ruling device. pairs of rigid lever arms 5 and 6 constitute the side portions of a numberof triangles of which the base portions are formed by the flexible body of the ruling device, which in the construction shown in Figs. 5 to 7 inclusive, comprises the flexible, resilient steel bands 1 and 2 and the flexible ruling member 3. The triangles th'us formed-preferably overlap, as shown, to render the ruling device rigid when the flexible members 1 and 2 are secured by the screw 18 in adjustod position and preferably, also, as

shown, the companion arms 5' and 6 of'each pair are oppositely inclined. The arms 5 and 6 are rigidl connected to the flexible members or ban s 1 and 2, so that, as the latter are relatively shifted in longitudinal body and the lines c-c are-the efiective lines of thearms, Since the lever arms are rig dly connected to the flexible 'body. of the SCIlbeI','thB angles 3 between each line a e and the corresponding line d-d remains the same in all of the different adjusted positions of the relatively shiftable,

flexible members or bands 1 and 2. In con- The sequence of this arrangement, the, flexible,

body of the curve scriber and its ruling edge will be bent to forma. regular curve when the flexible members or bands 1 and 2are relatively; shifted in ion itudinal direction to move the inner ends 0 eachcpairofpivotod arms together or apart, and, inasmuch as the arrangement of the arms is preferably uniform, throughout, the curve will ands be the true are of a circle, If the are adjusted to move the inner ends 'f 'th pivoted pairs of arms ig. 3, the flexible body of the ruling device will lie-bent to form a convex arc, and if the flexible members or bands 1 -and 2 are adjusted to move the inner ends of the pairs of arms together, the flexible body of the band is bent to form a concave arc.'

The curve scriber can be readily and guickly'set to form an arc of desired rains, and when once set, can be held in p sition by the clamp screw 18 The tendency of the resilient metal bands land 2 and'of the member 3 is to spring back to straight line position and this res liency of ,thc'parts takes'up all lost motion in the construction, so that the rulin devioe'jia an.

apart, as show in apart, has a sing curately held in the are to which it is adjusted. The flexible member 3 which, as stated, is provided with an ofiset shoulder 3' at its lower edge, if desired, may be provided with a similar shoulder at its upper edge, so that the ruling device can be used with either side uppermost. In the forms shown in Figs. 1 to 7 it is essential that the flexible'ruling membcrB shall be slidably connected to at least one of the flexible members or hands 1 and 2, but preferably, as shown, it is slidably connected to both, so that it may be removed and another similar ruling member substituted therefor. In this way a number of ruling members having different scales thereon may be conveniently employed in connection with the improved curve scriber.

The improved device is well adapted for use by draftsmen in laying out railway track structures and obviates the necessity of using a large number of arc shaped rulers of diiferent curvature. It may also be used to advantage by other draftsmen and by model makers for laying out circular arcs. In the form of the invention shown in Figs. 8 to 14, inclusive, the flexible body of the device, instead of having two, longitudinally shiftable, flexible members or hands for moving the pivoted arms together and e longitudinal, flexible rod 19, for performing this function. One end of this rod is provided with ri ht-hand screw threads and the other with oft-hand threads and the intermediate portion of the rod comprises a number of alternately arranged and oppositely threaded short sections. That is to say, the end portion f and the short sections 3 are provided with right hand threads an the opposite end 9 and the short sections 9' are provided with left hand threads, the sections f and g alternating, as clearlyindicated in Figs. 8, 9 and 10. The two series of lever arms 20 and 21 are preferably oppositely inclined and over lapped, as shown. These arms are formed of flat metal strips which are provided at their inner ends with angularly offset portions that are bent back upon themselves to form

eyes

22 and 23, through which the flexible screw rod 19 extends. The inner ends of the lower set of arms 20 are bent upwardly around the rod to form the eyes 22, as most clearly shown in Fig. 12, and the inner ends of the arms 21 of the uppermost series are bent downwardly around the screw I rod to form the eyes 23, as most clearly shown in Fig. 14. The eyes 23 on the arms 21 engage the right-hand threaded sections f and f of the flexible screw rod and the eyes 22 of the arms 20 engage the left-hand threaded sections 9 and g, the eyes being providetlwith suitable interior threads for cngaging the right and left-hand threads of the rod. In order that the arms may be vner end which forms an enlarged dou end of the device is -19 .is provi readily assembled, they are placed on the rod ,with the eyes thereof somewhat open, as

shown in Fig. 14, and the eyes are then clamped upon the rod by screws 24 extending through the overlapped sections thereof. Each arm 20 of one series is pivotally connected at its outer end to the outer end of a companion arm 21 of the other series by a pivot screw 25'having a nut 26 threaded ,on its lower end. To more securely hold' the overlapped arms .in engagement; thin metalstrips 20' ext/end longitudinally over the arms 20 and are'secured at its ends to the opposite ends of these arms by the screws 24 and pivot screws 25, as most clearly shown in Fig. 12. These strips 20' are spaced apart from the arms 20 and the arms 21 fit between the arms 20 and the overlapping strips 20'. The arm 20" at the left-hand end of i the ruler is provided with an-enlargfld ine eye 22. Similarly, the arm 21 at the right-hand I provided with an enlarged inner end which forms a long eye 23'. The right-hand end of the screw rod ed with a linger piece 27 by which the rod can be rotated'to move the inner face of each pair of pivoted arms 20 and 21 together or apart and, inasmuch as the lever arms are held at fixed angles to the flexible screw rod, the latter is thus bent to form arcs of greater or less radius in accordance with the,extent. to which the inner ends of the arms 'are ad'usted along the screw rod. A longitudina flexible member 28 of hard rubber, celluloid or the like, forms part of the longitudinal I flexible body of the ruler and is preferably arranged beneath the flexible screw rod 19. This flexible member is secured to the set of, arms 21 by means of screws 29 which extend throu downturned lugs 30 on the inner ends of t e arms 21. At the left-hand end of the device the flexible ruling. member 28 is slidably connected to the end'arm 20" and the adja' cent arm 20 by pieces 81, secured tothe under side of these arms at their inner ends by the screws 24 and having downturnedjugs 32 the inner and outer faces of the flexib ember 28, as shown in Figs. 8 and 1 The lower portion of the flexiblemember is preferably provided with. a longitudinal! ex: tended, projecting a convenient ruling edge. The lower face of the flexible ruling member 28*lies;in the same horizontal plane with the loweriends of the nuts 26, so that the device is conveniently and properly supported upon a fiat surface, such as indicated by the line b-b in 12. In this form, as in that previously described the rigid lever arms are maintained'at fixed angles to the flexible body of the curve scriber and to the ruling edge thereof, as indicated by the lines 'cc and d-din Figs.

shoulder 28' which orms 9 and 10, so thatla's the inner ends of the lever arms are moved together and apart the flexible member a'nd, its ruling edge is bent to regular curves or arcs which vary in ac cordance with the extent to which the inner ends'of the pairs of pivoted arms are adjusted. In the form shown in Figs. 8,9 and 10,.the inner ends of the arms abut is the straight line position of the ruling device, so'that this articular arrangement could only be used or drawing convex arcs.

In the forms shown in Figs. '15 to 19, in-

elusive, like thatshown in Figs. 1 to 7, inclusive, the longitudinal flexible body of the extend through and are slidably connected by a'jserie's o loops 39 and 40 formed upon the inner ends of the arms and 36. The loops 39 on the arms 35 are rigidly connected to/the band 37 by screws 41 an the loops are rigidly connected to the band 38' by screws 42, these screws being preferably provided with nuts43, as shown. The loops 39 and 40 ,on both sets of armssurround both-of the bands37 and 38, but, as stated.

theloop s 39 of the arms 35 are only rigidly connected to the band 37, while the loops 40 of the arms 36 are only rigidly connected to the band 38. The flexible member of celluloid, rubber or the like, iss'imilar't'o that hown in Figs. 1' to 7, inclusive, but instead,

of directly engaging the bands, the grooves,

in its uppe'r and lower edges are arranged to engage the inturned ends ofa series of U- shaped holders 44, which are mounted upon some of the loops 39 and 40 and are secured thereto by the

screws

41 and 42 respectively. The end arm 36- is providedrwith a flange '13 and a loop 40. A loop 39', secured to the band 37 1s provided'with a flange 14*,

' and these flanges are provided with aislid able connection and a clamping-screw 18,

similar to that shown in Figs. 2, 3 and 7. In the form shownin Figs; 17 to 19, in-

clusive, the lever arms of the device indicated by the numerals 45-and 46 are provided with circular outer ends connected by ivots similar to those shown: in Big. 6.

'e hese arms are'fwider at theirinner ends thaii at their outer ends, are formed of sheet. metal and are provided with'ou'tturned "edge flanges 47. The body orweb portions of these arms terminate short of their inner ends, but the flanges extend bgyond the body or web portions thereof an are provided with ofi'set inner ends which are con nected respectively to the two flexible meme bers or hands 49 and 50, which extend Ion? gitudinally of the ruler, the extended flanges or feet at the inner ends of the arms bclng secured to the respective hands by screws-51 having nuts 52 thereon.

The flanges 13" and 14 are similarly respectively connected to the bands and these flangesare provided with a clamp screw 18 similar to that shown in 2, 3, 4 and 7. In this form, the

flexible member 3 is provided with a series of screws 53 which project from the rear central portion thereof. The shanks of these screws extend between the inner adjacent ends of the bands 49 and 50, and the headsthereof engage the inner faces of the bands.

The rear face of the flexible member'aabuts against the outer ends of the screws fil-and clips 54 connected by screws '55 to theedgesf of the flexible member, extend inwardly and engage the edges of the bands to strengthen the structure and prevent the bands froln separating. In this latte!- form, the central lines of the arms are always maintained at.

fixed angles to the flexible body of the ruler or at fixed angles to lines drawn at right angles to theruling edge of the device, as indicated by the lines c0 and dd in Figs. 17 and 18. I It is obvious that the improved adjustable curve scriber may be embodied in various forms without departure from the essentials of the-invention as defined in the claims.

While the inner ends of the airs of pivoted arms are preferably moved together and a art by two longitudinal, slidably connecte flexible members, one at least of which is formed of resilient material, other means may be employed for this pur so, such, for

"example, as the screw rod of t e' form'illustrated in Figs.'8 to 14, inclusive. It is only essential that.- the arms bemaintained at fixed angles to the flexible body of the ruling device. :It is alsoobvious that thear rangement of the parts may bdmodified.

without. departure from/the essentials.

the invention as defined in thefclaims. I 1

1 claim as'iny invention 1. An adjustable; curve so be: comprising.

a longitudinal flexible bod and two series of lever arms mounted orijs'aid flexible body at fixed angles thereto, each arm'of one series being pivotally connected to the companion arm of the other-'s erieathe' arms of each series being mountedon said flexible body. in-

dependently of the arms of the other series and said separate series of arms being. relatively shiftable together and apart.

2. An adjustable curve scriber comprising a longitudinal fiexible body and .two series of oppositely inclined, overlapping rigid arms mounted at their innerends on said flexible body at angles thereto, each arm of one series being pivotally connected two series of rigid arms,

series being pivotall inner ends of t at itsiouter end to the corresplonding end of a cm fianion arm of the ot er series and said arms. the side portions of a series 0t overlapp triangles of which the rtions are orined by the common flexib e body, one series of arms being shiftable relatively to the other series.

8. An adjustable curve ruler having a flexible body. rovided with a ruling e ge two series of ever arms mounted on sai flexible body, each arm of one series being pivotally connected to the coin anion arm of the other series, said arms in maintained at fixed angles to said flexib e body and said body comprising suitable means for shifting one series of arms relatively to the other series.

4. An adjustable curve scriber having a flexible body and two series of rigid lever arms mounted at their inner ends on said flexible body at fixed angles thereto, each arm of one series being pivotally connected at its outer end to the companion arm of the opposite series, the inner ends of the arms of one series bein shiftable relatively to the 0 arms of the other series, and said flexible body having suitable means connecting the inner ends of the arms of each series.

5. An adjustable curve scriber comprising a longitudinal, flexible body having a ruling edge and a number of pairs of uniform, o

ositely inclined, rigid arms mounted on said flexible bed at uni orm fixed angles thereto, and pivota connections between the outer ends of the arms of each pair, said flexible body com rising suitable means for relatively shi ting the points of mounting of said arms to increhsewr decrease the angles between the pivoted arms of each pair.

6. An adjustable curve scriber comprising each arm of one connected to a companion arm in the ot er series and the arms of each pivotally connected pair bein%op ositely inclined, and a longitudinal exi le body comprising means for shifting the arms of one series to and from the arms of the other series, said arms bein maintained at fixed angles to said flexible y.

7. An adjustable curve scriber comprising two lon 'tudinal, slidably connected, flexible mem rs arranged adjacent each other, a number of rigid arms connected attheir inner ends to one of said flexible members at fixed angles thereto, and connections between the outer ends of said arms and the other of said flexible members, said arms and said connections being arranged upon the same side of both of said members and said connections being pivoted at their outer ends to the outer ends of said arms.

An adjustable curve .scriber coin rising two lon itudinal, slidabl conncc flexible mem rs, and a number of arms pivotally connected 'in pairs, the arms of each pair being rigidly connected respectively one to each of'said flexible members.

two lon itudinal, slidably connec flexible members, a number of pairs of ri 'd lever arms mounted at fixed a les to sai flexible members with the-arms 0 together and connected respectively one to each of said members and means for holding said relatively slidable, different ad'usted itions.

10. An a justab e curve scriber com rising two flexible, resilient bands relatively shiftable in longitudinal direction, a series of inclined arms connected to one of said bands at fixed angles thereto, a second series of inclined arms overla ping the first series .and connected to the ot fixed angles thereto and pivotal connections between one arm of each series and a companion arm of the other series.

11. An adjustable curve scriber comprising two, flexible, longitudinal mem rs relativel shiftable in lo 'tudinal direction, a num r of .pairs of ri d lever arms mounted at fixed angles to sai flexible members with the arms 0 each air pivotally connected together and rigidly connected respectively one to each of said flexible members, and a third flexible member having a ruling edge removably connected to said first mentioned flexible members.

12. An adgustable curve scriber com rising t-wo flexi le, slidably connected, resi ient bands, two series of oppositely inclined, overlapping, lever arms mounted respectively on said bands at fixed angles thereto, pivotal connections between the ends of the companion arms of the two series, and means for holding said bands in diflerent relative positions. 13. An adjustable curve scriber, comprisin two resilient, metal bands relatively shiftable in longitudinal direction, a number of pairs of rigid lever arms, the arms of each pair being ivotally connected attheir outer ends and rigidly connected at their inner ends one to each of said bands, and means for holding said bands in different adjusted positions.

14. An adjustable curve scriber com rising two resilient, metal bands relatively shiftable in lon itudinal direction, a number of pairs of rigid lever arms, the arms of each pair being pivotally connected at their outer ends and rigidly connected at their inner ends one to, each of said bands and a flexible member having a ruling e e removabl connected to said bands and engitudiiial y shiftable thereon.

15. Anadjustable curve scriber comprismg two, resi ient, slidably connected metal, bands arranged .ed e to edge'and relatively shiftable in longitu inal direction, two series 9. An adjustable curve scriber cotgilprising er of said bands ateach pair pivoted flexible members in .of oppositely inclined, overlapping arms rigidly connected respectively to said bands, pivotal connections between each arm of one series and a com anion arm of the other series and means or holding said bands in diflerent ad'usted positions.

16. An :1 justable curve scriber comprising two, flexible, resilient bands relatively shlftable in longitudinal direction, a number of pairs of oppositely inclined, rigid,

lever arms, the arms of each pair being pivotally connected at their outer ends and ri idly connected at their inner divergent ends one to each of said bands, means for holding saidbands in different adjusted positions, and a longitudinal flexible member having a ruling ed e mounted on said bands.

17. An a 'ustable curve scriber com rising two slida ly connected, flexible mem era, a. number of pairs of arms formed of sheet metal, the arms of each pair being rigidly connected at their inner ends oneto each of said members,.andhaving oppositely concaved, overlapping outer endportions and flanged pivots extending through said concaved outer end ortions.

18. An adjusta 1e curve scriber comprising two slidablyconnected, resilient metal bands, a number of pairs of rigid lever arms formed of corrugated sheet metal, the arms of each pair being rigidly connected at their inner endsone to each of said bands and having circular, oppositel concaved, overlapping outer ends, and anged pivots ex tending through the concaved outer ends of said pairs of arms.

19. An adjustable curve scriber comprising two, flexible, resilient bands relatively shiftable in lon itudinal direction, a number of pairs 0? oppositely inclined rigid lever arms, thearms of eac 1 pair being pivotally connected at their outer ends and rigidly connccted at their inner divergent ends one to each of said bands, and a flexible rul ing member having grooved upper and lower edges slidably mounted on said bands.

20. An ad ustable curve scriber compris ing two, slidably connected, resilient bands formed of sheet metal and each having a series of arms integral therewith and ar ranged in a plane at right an les thereto, pivots connecting the arms 0 one series with companion arms of the other series,

and means for holding said bands in dif;

ferent adjusted positions. I

21. An adjustable curve scriber comprising two resilient sheet metal bands each having a series of inclined arms integral therewith and arranged in a plane at right angles thereto, pivots connecting the arms of one series with companion arms of the other series, and a fiexible'lruling member having grooves in its upper and lower edges for receiving the inner adjacent edges of said bands, the latter being relativel shift able along said flexible member, an means for holding said bands in difl'erent adjusted positions.

22.. An adjustable curve scriber comprising'a body portion formed of two, parallel flexible members arranged closely adjacent each other and relatively shiftable in longitudinal direction only, and a series of jointed arms connected to said members and arranged on one side thereof in planssub nections between the ends of the arms of one