US2107449A

US2107449A - Exercising machine

Info

Publication number: US2107449A
Application number: US53124A
Authority: US
Inventors: Harold J Marlowe
Original assignee: MARLOWE PRODUCTS Inc
Current assignee: MARLOWE PRODUCTS Inc
Priority date: 1935-12-06
Filing date: 1935-12-06
Publication date: 1938-02-08
Anticipated expiration: 1955-02-08
Also published as: FR809238A; GB478675A; CH195098A

Description

Feb. 8, 1938. H. J. MKRLOWE EXERCISING MACHINE 4 Sheets-Sheet 1 Filed Dec. 6, 1935 ATTORNEYS Fb. 8, 1938. J MARL'QWE 2,107,449"

.EXERCISING MACHINE Filed Dec. 6, 1935 4 Sheets-Sheet 2- INVENTOR fiar'ola JMrlowe L61 WW ATTORNEYS Feb. 8, I H. J. MARLOWE I 2,107,449

EXERCIS ING MACHINE.

Filed Dec. 6, 1935 4 Sheets-Sheet s .55 .55 Jy aa e0 V A I & 65

INVENTOR JiaralaJflir/owa ATTORNEYS Feb. 8, 1938. J MARLOWE 2,107,449

EXERCISING MACHINE Filed Dec. 6, 1935 4 Sheets-Sheet 4 P w Z w 0 E T N M R E 0 W H [Um A r f i a Sm. a Rm .& WWWM 2W Q :R ER

Q RR

REESSUE Patented Feb. 8, 1938- JUN 2 1942 Application December 6, 1935, Serial No. 53,124

28 Claims.

My present invention is concerned with exercising machines and has among its objects to provide a simple and rugged apparatus, which serves effectively to exercise those muscles commonly used in bicycle riding, and in horseback riding, as well as those used in operating a rowing machine.

An object of the invention is to provide a machine of the above type, in which the user does not exert affirmative effort, but, on the contrary, muscular movement is mechanically imposed upon him regardless of whether he tries to relax or to resist such movement.

Another object is to provide a machine of the above type, capable of being operated from a fractional horsepower motor, which will yet afford exercise-adequate for even powerful indi-- viduals. I

Another object is to provide a device of the above type, by which the complex rhythmic relative movements of the legs, arms and body of the user are effected, with the use of conventional transmission gearing and linkage not subject to jamming or noisy operation.

Another object is to provide a machine of the above type which admits of ready adjustment with respect to the height, weight and age of the user.

Another object is to provide a machine of the above type, which in operation will not cause any injury to the floor, rug or other support on which it may stand when used in any ordinary room of a dwelling.

The invention involves a support frame or chassis carrying a pedal crank member, a seat and a-handle bar, and an electric motor operating the pedal through a gear reduction, and preferably also connected by linkage to said seat and handle member for moving the same in a cycle by which is brought about the desired coordinated exercising movement of the user.

In a preferred embodiment the chassis carries a transmission box driven from the motor and driving the pedal crank shaft, preferably through a worm drive, and also driving the seat and handle supports, preferably by means of a connecting rod, protruding from the transmission box and operated from a crank or othereccentric member therein which is driven from the pedal crank shaft.

Preferably a generally horizontal control bar pivoted to the frame is operated from the connecting rod, the movement of said control bar being resisted by a coil spring connecting the free end of said bar to the frame and the tension of which is controlled by adjustably positioning the upper spring carriage thereof along said control bar. The seat and handle bar are mounted on corresponding support bars, one ofwhich, preferably the seat carrying bar, is pivoted to the frame, the other, preferably the handle bar, pivoted at one end thereof, to the first of said bars, and between its ends to said control bar.

In the accompanying drawings, in which are shown one or more of various possible embodi-,

ments of the several features of the invention,

Fig. 1 is a plan view of the machine,

Fig. 2 isa side elevation thereof showing the operation thereof,

Fig. 3 is a front elevation of the machine,

Fig. 4 is a sectional view on an enlarged scale with parts broken away taken along the line 44 of. Fig. l,

Fig. 5 is a View in transverse cross-section through the transmission box taken on line 55 of Fig. 4,

Fig. 6 is a view similar to Fig. 4 with parts broken away showing an alternative embodiment of transmission box,

Fig. 7 is a sectional view taken on line 1-'| of Fig. 6,

Fig. 8 is a detail sectional View taken on line 8-8 of Fig. 6,

Fig. 9 is a plan view showing the spring tension adjustment scale, and

Fig. 10 is a detail sectional view taken on line Ill-l of Fig. 4.

Referring now to the drawings, the device comprises a chassis or frame, preferably made of metal tube stock, which may include a pair of transverse and inwardly inclined U-shaped foot members I I the legs of each of which are connected at their ends by a transverse brace II. The foot members are connected by a pair of longitudinal rods l3 forming the chassis. Each of rods I3 is reversely bent at its forward end to form a trapezoidal side frame l with a horizontal upper base Hi the downturned extremity of each rod being welded at I! to the longitudinal portion l3 thereof. Longitudinal brace rods I8 are connected at their ends to the respective cross braces 12 and their intermediate portion extends horizontally at l9 under, along and in contact with the chassis rods I3 to which they may also be welded.

Upon the chassis and between the side frame pieces 15 is mounted the transmission box B,

hereinafter to be described. It may be attached by screw I02 threaded into boss I03 and exerting pressure through clamp plate )4 against brace rods l9. Through the lateral walls of box B protrudes the pedal crank shaft 20 mounting the' 21 which may be a more or less conventional motorcycle seat, and is preferably of metal, is mounted by its central fin 28 to the upper end of a bar 29, the lower end of which is pivoted at 38 preferably to a fin 3| cast on the transmission box B.

The handle bar 32, which may be similar to that of a motorcycle, is centrally clamped in a corresponding collar 33 at the upper end of a supporting bar 34 therefor, the lower end of which bar is pivoted at 35 to'the seat supporting bar 29 and which is pivoted between its ends asat 36 to the extremity of the control bar 25. Preferably, the collar 33 has the usual clamping screw 31 thereon for adjustably positioning the handle grips 32' in accordance with the arm length of the user.

If the seat 21 were rigidly mounted upon its support bar 29 it would tilt with the movement of said bar in pivoting about pin 30. A parallel motion linkage is, therefore, provided to assure substantially a translational movement? of said seat parallel to itself. For this purpose, the mount of the seat 21 on the bar 29 is'by means of a pivot screw 38 and a parallel motion link 39 is pivoted at its upper end to the front of the seat at 48, and its opposite end, (formed as a clevis 4| straddling .the bar 34) is preferably pivotally mounted on pins 42 at corresponding ears 43 welded to the side frame I5.

To resist thepivotal motion imparted by the connecting rod 23 to the control bar 25 a heavy coil spring 44 is provided, pivotally anchored to the frame at one end and to the control bar at the other. The frame mount may comprise a screw 41 with a spherical head 46 housed in a corresponding socket 48 in a foot 45 cast with the box B. The shank of screw 41 is screwed through the button 49 whichis gripped by the lower turns of the spring 44. The upper end of the spring has a corresponding button 58 pivoted at to a carriage 52 formed as a'sleeve which encircles the control bar 25. A screw 53 threaded through said carriage 52 is rotatably mounted at its ends in corresponding ears 54 on the control bar. By means of a handle 55 at the forward end, the screw 53 is turned and the carriage 52 thereby caused to be moved forward or backward to the desired position, for adjusting the tension of the spring 44. Preferably, as best shown in Fig. 9, a slotted scale plate 56 is attached at 58 upon corresponding studs 51 .on top of the control bar' stud 59 on'top of the carriage 52 travels in longitudinal slot 69 in the plate, to indicate the setting, preferably in terms of the weight of the user.

While, of course, it would be possible, to arrangethe parts substantially as in my copending application, Serial No. 733,546 of July 3, 1934 to operate the pedals by footpower, which in turn causes the movement of the seat and handle bars, it is preferred, according to the present invention, tooperate the apparatus by a mechanical power drive. i For this purpose, a fractional horse power electrical motor 6| is mounted, preferably at the rear end of, the chassis and is connected by means of a drive shaft 62 to the transmission box.

While drive may be effected through any desired clutch, the drive shaft 62 is illustratively shown as a hollow shaft operating within a fixed tube 3|, and having a squared extremity 62' telescoped over the correspondingly flattened protruding extremity 63 of cross shaft 64 bearing in the front and back walls 65 and 66 of the transmission box B. A worm 61 upon said shaft 64 meshes with a worm wheel 58 keyed to the pedal crankshaft 20, which bears in the lateral walls 69 and of the transmission box B.

The pedal crankshaft 20 also serves to deliver power to the connecting rod 23, by which the seat and handle mounting bars are operated. For this purpose a gear 1| keyed to shaft 29 meshes with an idler gear 12 on stub shaft 13 in the transmission box, which, in turn, meshes with drive gear "on transmission crankshaft near the upper part of the box. The crank 16 of shaft 15 affords the bearing for the lower end of the connecting rod 23. That rod preferably protrudes from the upper wall 11 of the box through a stufiing box 18 resiliently tightened by a coil spring 19 about the protruding end of the connecting rod 23 and reacting at its upper end, against flange 88.

The use of the apparatus will be obvious from the above description. It may be briefly noted that after the user mounts the apparatus, as he would a motorcycle, and places his feet on the pedals, he sets the electric motor 6| into action by throwing the switch (not shown) which may be disposed at any convenient accessible place. The worm gear reduction 61-68 is such as to cause driving of the pedal crankshaft at the rate of about 80 revolutions per minute. At the same time transmission crank 16 will move at desired speed, determined by the ratio of gears 1| and 14, preferably at approximately thirty revolutions per minute. In this operation, the rear of control bar will move downward about pivot 26, the forward end moving correspondingly upward and stressing the spring 44. In the downward pivoting of the rear of the control bar, the handle support bar 34 is lowered therewith, said bar 34 correspondingly depressing the seat suppart bar 29 about its pivot 30, by virtue of the thrust delivered through pivot 35. The portion of the control bar 25 between the

pivots

26 and 36, forms with the portion of the handle support bar 34 between the pivots and 36 a toggle, so that said pivots 35 and 36 moving through distinct paths cause said bar 34 to tilt forward about pivot 35 and about the control bar pivot 36. The extreme position of the downward and rearward movement of seat 21 and the concurrent downward and forward movement of handle bar 32 (shown in Fig. 2 in dotted lines) is reached when the transmission crank 16 has reached lower dead center. As the crank 16 passes dead center position, the stressed spring 44 aids the motor in the return movement, in which the seat 21 and the handle bar 32 perform the reverse of the motion previously set forth, and reach their position of closest approach when crank 16 reaches upper dead center.

Thus in operation, the user, without exerting any affirmative effort, is constrained to perform repeated cycles of vigorous muscular movements. His legs are caused to perform a pedalling motion. At the. same time his trunk and arms are caused alternately to be bent over and stretched by the rearward movement of the seat and the concurrent forward movement of the handle bars and then to be straightened and relaxed by the return movement of the seat and handle bar.

In the pivoting movement of seat mounting bar 29, the seat 21 moves through a translational path, at no time tilting from horizontal, since the parallel motion link 39 compensates for the is generally similar to that described, except that it includes selective gear reduction for greater flexibility of operation, in accordance with the physical condition of the user. Corresponding parts bear the same reference numerals, primed.

In general, the transmission box B resembles that of the other embodiments, but it differs in that the worm 61' is on .a countershaft 90 parallel to the motor driven shaft 64' and propelled at either of two alternative power speed reductions depending on the setting of a gear shift. For this purpose, a pair of alternative driving gears 9i and 92 are keyed on shaft 64' and a pairof alternative driven gears 93 and 94 are loosely mounted on countershaft 90. The gear trans-. mission 92, 94, affords a greater reduction than the gear transmission 9|, 93, because the drive gear 92 of the former is smaller and the driven gear 94 is larger than the corresponding elements of the alternative drive. Driven gears 93 and 94.

have clutch teeth 95, alternatively engaged by correspondingly conformed teeth on clutch sleeve 96 keyed to countershaft 90 between gears93 and 94, and positioned by means of a yoke 91 straddling the same, the shank of which yoke is mounted on the end of an arm 99 which may be turned by means of an exposed handle I00. A coil spring llil resiliently retains the clutch 96 in one'or the other of the-two positions as desired. The transmission box of Figs. 6 to 8 is interchangeable with that of Figs. 3 and 4, and admits of either a fast operation of the pedal say at 80 R. P. M. or a slower operation say at 40 R. P. lVL, in each of which the motor 8i operates on full voltage. F

It will thus be seen that there is herein described apparatus in which the several features of this invention are embodied, and which apparatus in its action attains the various objects of the invention and is well suited 'to meet the requirements of practical use.

As many changes could be made in the above construction, and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying draw ingsshallbe interpreted has illustrative and not in a limiting sense.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. An exercising machine comprising a.sup-

port base, a handle member, a seat member, and pedal cranks on said support, an electric motor having a speed reducing connection for propelhng control bar pivoted between its ends to said frame,

and pivoted near its forward end to said .handle carryingbar, pedal cranks positioned laterally of said ,frame, and a transmission between said cranks and said control ban-serving in.operation alternately to-cause said'seat and said handle members tom'ove-toward andaway from each other.

' to said frame.

- 3. An exercising machine comprising a support base, a seat member having the upper end of a support bar attached thereunder, the opposite end of said bar having a fixed pivotal support with respect to said base, a second support.

bar pivoted to said seat support bar near one end thereof and carrying a handle bar at the upper end thereof, a control bar pivotally mounted on said base and secured near its rear end to one of said support bars, a pedal crank and a transmission between the latter and said control bar.

4. An exercising machine comprising a support base, having upstanding parallel frame pieces, a generally horizontal control bar pivoted between said frame pieces, a pedal movement having a transmission to said control bar, a seat, a support bar secured thereunder at one end thereof and pivoted to said frame at the opposite end thereof, a handle bar, and a support bar for the latter pivoted at one end to said seat support bar and pivoted between itsends to said control bar.

5. An exercising machine comprising a sup- ,port base having upstanding parallel frame pieces,

a generally horizontal control bar pivoted between said frame pieces, a pedal movement having a transmission to said control bar, a seat, a support bar secured thereunder at one end and pivoted to said frame at the opposite end, a handle bar,

a support bar for the latter pivoted at o ne end to' said seat-support bar and pivoted between its ends to said control bar, said seat having a pivotal mount on the seat support bar, and a parallel A motion link pivoted at one end to the forward part 'its pivot, a seat member and a handle bar member, support bars respectively mounting the same, one of said bars having a. fixed pivotal support on said. frame and the other being pivoted to said control bar, the lower end of one of said support bars being pivoted to an intermediate portion of the other of said support bars.'

7. An exercising machine including a pair of parallel lateral frame members, a control bar pivoted between said members, a pedal crank member having a transmission connected to said control bar for movement of the latter about its pivot, a seat member and a handle bar member, support bars respectively mountingthe same, one

- of said bars being pivoted to said frame and the other pivoted to said control bar, the lower end of one of said bars pivoted to an intermediate portion of the other of said bars, said seat having a pivotal mount on the support bar thereof, and

v a parallel motion link for said seat, pivoted at one end to the front of said seat and at the other end 8. An exercising machine including a pair of parallel lateral frame members, a control bar pivoted between said members, a pedal crank .member having a transmission connected to said control bar for movement of the latter about its pivot, a seat member and a handle bar member,

support bars respectively mounting the same; one of said bars being pivoted to said frame and'th'e other pivoted to said control bar, the lower end of one of said bars pivoted to an intermediate portion of the other of said bars, said seat having a pivotal mount on the support bar thereof and a parallel motion link pivoted at itsrear end to the front of said seat and having a clevis at the other end straddling the handle support bar and pivoted at its extremities to said frame.

9. An exercising machine comprising a support frame, including a pair of parallel lateral members, a generally horizontal control bar pivotally mounted between said lateral members, an adjustable resistance coil spring attached at its lower end to said frame, and attached at its upper end to the forward part of said control bar, means for adjusting the position of the upper end of said spring lengthwise of said control bar to determine the tension thereof, a pedal crank member, linkage connecting the same to said control bar to efiect a pivoting movement of the latter, a seat member and a handle bar member and linkage connecting said control bar to said respective members to effect relative movement thereof during the stressing of said resistance spring and reverse relative movement thereof during the return of said spring.

10. An exercising machine comprising a support base, a seat, a handle member, a bar pivoted to the frame and mounting one of said members at its upper end, a bar pivoted at one end to said first bar, and mounting the other of said members at its upper end,fa control bar pivoted to said frame and having a pivotal connection at one end to said second bar, a coil resistance spring mounted at its lower end to saidframe, and having a carriageafllxed at its upper end to the forward end of said control bar, and a screw and nut connection for said spring. carriage longitudinally of said control bar to adjusted position thereof, said carriage having an indicatorand a scale on the control bar for registering the setting in accordance with the weight of the user.

11. An exercising machine including a support frame, a pedal crank member, a seat, a support bar for said seat pivoted at its upper end with respect to the base of said seat, and pivoted at its lower end to said frame, a linkage for moving said support her about the pivot of the latter inthe movement of the pedal crank member, and means for maintaining the seat in horizontal position throughout by movementabout the pivot support,

said seat and said handle bar to cause the latter alternately to move toward and away from each other.

13. An exercising machine'comprising a support base, a movable seat, and a movable handle bar supported on said base, a transmission box on said base, a pedal crank member carried thereby, an electric motor on said base, a speed reducing transmission in said box for delivering torque from said motor to said pedal crank, said box having a further speed reduction transmission to said seat and said handle bar to cause the latter to move relative to eachother, said linkage including a pivoted control bar operated from said transmission box and governing the movement of both said seat and said handle bar, and an adjustable resistance spring connecting an end of said control bar to said support base.

14. An exercising machine comprising a support frame, a seat and a handle bar carried thereon, a transmission box, pedal crank members extending from opposite sides of said transmission box, an electric motor on said frame, and a worm drive connection between said motor and said pedal crank for power drive of said pedals and means transmitting torque from said electric motor to move said seat and handle bar relative to each other.

15. An exercising machine comprising a support base, having a pair of lateral frame members a transmission box mounted onsaid.

base, a shaft transversely therethrough having crank pedals on the ends thereof, a generally horizontal control bar pivoted between said frame members, a crank rod extending upward from said transmission box and pivoted to said control bar, an adjustable coil spring mounted at its lower end on said frame and a carriage for the upper end thereof slidably adjustable on said control bar for setting the spring tension, a seat member and a handle bar member, bars supporting the respective members, one of said bars being pivoted at one end to the frame, the other of aid bars pivoted at one end to said first bar and pivoted between its ends to said control bar.

16. An exercising machine comprising a sup' portbasehavingapairofsimilarlateralmembets, 9. transmission box mounted on said base, a shaft transversely therethrough having pedal cranks on the ends-thereof, a generally horizontal control bar pivoted between said lateral a connecting rod extending upward from said transmission box and pivotedto said control her, an adjustable coil springailixed at one end to said frame andhaving a carriage at the opposite end slidably adjustable on said control bar for setting thespringtensiomaseatmemberandahandle bar member, bars pivotally the respective members, one of said bars being pivoted at one end to the frame, the other of said bars pivotedat oneendtosaidflrstbar, andpivoted between its ends to said control bar, and an electric motor mounted on said surmort base, havmg a worm drive connection within said transmission box to saidpedal shaft and having a reduction gear ton within said box to said connecting rod.

l'LTIn an exercising machine, the confirmationofaonbomhavmg a driveshslt longitudinally therethrough, and a pedal crank =shaft tramversely therethrough; a worm drive connection between said drive shaft and said pedal crankshaft, a on for operating a seatandanoperatinghandleincludingatrlmmission crankshaft within said box lnving a connecting rod thereon, protruding from the box, and a reduction gearing on within aid box from said pedal crankshaft to said sion crankshaft.

18. An exercising machine comprising a frame of tube stock, includingtransverse floor rests;'longitudinal side rests, tube stock lateral memben rising from said base members, and a platform, an electric motor moimtedi-tbereon, a transm'wsion box mounted thereon between said lateral members, a drive shaft from said motor to said transmission box, said lateral tube stock members extending horizontally at the upper ends thereof, a control bar pivoted between said horizontal members, a connecting rod extending upward from said transmission box and pivoted tosaid control bar, a seat member, a handle bar member, support bars for said members, one of said support bars pivoted at one end to the other support bar and intermediate its ends to said control bar and a resistance spring connected at one end to said frame and at the other to the extremity of said control bar.

19. An exercising machine comprising a frame of tube stock, including transverse floor rests, longitudinal side rests, tube stock'lateralmembers rising from said base members, and forming a platform, an electric motor mounted thereon, a transmission box mounted thereon between said lateral members, a drive shaft from said motor to said transmission box, said lateral tube stock members extending horizontally at the upper ends thereof, a control bar pivoted between said horizontal members, a connecting rod extending upward from said transmission box and pivoted to said control bar, a seat member, a support bar therefor pivoted at its lower end to said-transmission box, a' handle bar member,a support bar therefor pivoted at its lower end to said seat support bar, and pivoted between its ends to said control bar, and a resistance coil spring having a carriage pivoted at its lower end to said frame and a carriage adjustably slidable at its upper end along said control bar.

20. An exercising machine comprising a frame of tube stock, including transverse floor rests, longitudinal chassis frame bars and tube stock lateral members rising from said chassis bars and forming a platform, an electric motor mounted on said chassis bars, a transmission box mounted on said chassis bars between said lateral members, a drive shaft from said motor to said transmission box, said lateral members extending horizontally at the upper ends thereof, a control bar pivoted between said horizontal members, a connecting rod extending upward from said transmission box and pivoted to said control bar, a seat member, a support bar therefor pivoted at its lower end to said transmission box, a handle bar, a support bar therefor pivoted at its lower end to said seat support bar, and pivoted between its ends to said control bar, and a reaction coil spring having a carriage pivoted at its lower end to said frame and a carriage adjustably slidable at its upper end along said control bar, said seat being pivoted near its back to the upper end of said seat carrying bar, and a parallel motion link pivoted at one end to said frame and at the other to the forward part of said seat.

21. An exercising machine comprising a frame structure, a seat, a handle, and means interlinking said seat and said handle with respect to said frame structure for moving said seat along a curved path while maintaining said seat in horizontal position throughout, and for simultaneously effecting a movement of said handle in direction opposed to that of said seat.

22. An exercising machine including a frame structure, a seat, a handle, means interlinking said seat and said handle with respect to said frame structure to cause them to move in curved generally opposed directions, and parallel motion linkage for maintaining said seat at a constant .inclination with respect to the horizontal during its movement.

23. An exercising machine including a frame structure, a bar having a'fixed pivotal support with respect to said structure, a second bar pivotally connected to said first bar, a control member having a fixed pivotal support with respect to to said latter bar whereby the movement of said bars .is constrained in generally opposed directions, a seat fixed to one of said bars against sliding movement, a handle supported on the other bar, and means for resisting the movement of said bars during a portion of their operating cycle.

25. An exercising machine including a frame structure, a bar having a fixed pivotal support with respect to said structure, a second bar pivotally connected to said first bar, a control member having a fixed pivotal support with respect to said latter bar whereby the movement of said bars is constrained in generally opposed direction, a seat fixed to one of said bars against sliding movement, a handle supported on the other bar, and spring means for resisting the movement of. said bars during a portion of their operating cycle, and reacting to aid return of said bars during the remainder of said cycle.

26. An exercising machine including a frame structure, a first bar having a fixed pivotal support with respect to said structure, a second bar pivotally connected to said first bar, a control member having a fixed pivotal support with respect to said frame structure, pivotally connected to said latter bar and forming with part of said latter bar a toggle for constraining the movement of said bars in opposed direction, a seat supported on one of said bars against sliding movement, and a handle support on the other bar.

27. An exercising machine including a frame structure, a seat supporting bar, a handle supporting bar, one of said bars having a fixed pivotal support with respect to said frame structure and pivotally connected to the other supporting bar, a control barhaving intermediate the ends there of a fixed pivotal support with respect to said frame structure, pivotally connected at one end to said latter supporting bar and forming with part of said. latter supporting bar a toggle for constraining the movement of said supporting bars in opposed directions, anda spring fixed at one end to said frame structure and pivotally connected at its other end to the other end of said control bar for resisting the movement of said supporting bars during a portion of their operating cycleand reacting to aid the return of said bars during the remainder of said cycle.

28. An exercising machine including a frame structure, a seat supporting bar, a handle supporting bar, one of said bars having a fixed pivotal support with respect to said frame structure and pivotally connected to the other supporting bar, a control member having a fixed pivotal support with respect to said frame structure, pivotally connected to said latter supporting bar above the pivotal connection between said supporting bars and forming with part of said latter supporting bar between its pivotal connections a toggle for' constraining the movement of said supporting bars in opposed directions.

HAROLD J. MARLOWE.