US2604726A - Toy mechanical scoop - Google Patents

Description

July 29, 1952 J. B. LOBB TOY MECHANICAL sc001 Filed March 22, 1949 5 Sheets-Sheet l Mm mm sw WW 9% w% July-29, 1952 J. B. LOBB TOY MECHANICAL SCQOP' 5 Sheets-S'neet 2 Filed March 22, 1949 J. B. LOBB TOY MECHANICAL 5000? July 29, 1952 Filed March 22, 1949 5 Sheets-Sheet 5 MENTOR, JOHN B L 053 y s I I u Jira.5.

July 29, 1952 5 Sheets-Sheet 4 Filed March 22, 1949 J 29, 1952 Y J. B. LOBB 2,604,726

' TOY MECHANICAL SCOOP Filed March 22, 1949 S Sheets-Sheet 5 Patented July 29, 1952 OFFICE TOY MECHANICAL SCOOP John Buchanan Lobb, Southgate, London, 7

England Application March 22, 1949, Serial No. 82,855 In Great Britain March 19, 1948 13 Claims.

This invention has reference to mechanical toys or models. The primary object of the invention is to provide an improved toy in the form of a mechanical load lifting device such as a crane, grab or scoop in which a number of operations necessary for the transference of a load from one place to another are carried out by means of a power source such as a spring or electric motor carried "by the device, the operations being automatically effected in correct sequence and timing. A further object of the invention is to provide a device in the formof a toy or model as above set out in which the device includes a grab, bucket or pick up hook which is carried by a wheeled, tracked or other mobile structure, the sequence of operations including intermittent movement of the said structure, the pick up and discharge operations being performed whilst the structure is stationary, the device realistically simulating the normal'action of the full size load lifting device.

The device according to the invention may be in the form of a stationary or fixed platform, but the invention further contemplates the employment of a mobile platform or member, the geap ing from the main power source being coupled to the driving wheels orother members through a suitable mechanical device such as a cam and linkage actuatedby the power source to impart an interrupted drive to the platform. It will be understood that the pick up and unloading operation occurs while the platform is stationary and the arrangement may be such that the platform movement is unidirectional or is reciprocatory.

Preferably, the power source consists of a clockwork motor but said power source could be an electric motor or a steam engine. The invention may be applied to a device in which the pick up member consists of a scoop, or said member may be a hook, or agrab bucket, i. e. a bucket consisting of two'partspivoted onacommon-center .line, the parts. opening and closing jaw fashion, the mechanism including means for opening and closing .Lthe jaws at the appropriate times in the cycle of operations, or said member could be an electro-magnetic device.

In order that a clearunderstanding of the invention may be obtained reference will now be made to the accompanying drawings illustrative of preferred forms of the invention, wherein:

Figure 1 is a sidevi'ew of one form, wherein the cabin is mounted ona fixed base to turn on a vertical axis,- the jib arm being shown in the loading or pick up position;

Figure 2 is a view looking from the left hand side of Fig. 1 with the cabin turned through The arm where shown in full lines is in the discharging position and where shown in broken lines in the normal or carrying position;

Figure 3 is a plan view of the operating mechanism;

Figure 4 is a sectional view on the line IV-IV,

Figure 3; V v

Figure 5 is a plan view showing an alternative mechanism for use with a mobile crane or the like wherein in addition to cabin turning and jib movement, the wheeled mounting platform is driven so as to move back and forth during appropriate periods in the cycle of operations;

Figure 6 is a sectional side view on the line VL-VI Figure 5; s

Figure '7 is a fragmentary side view of an alternative mechanism in which the wheeled plat form has an intermittent unidirectional movement imparted thereto; V

Figure 8 is a sectional view VIII-VIII Figure 7, and

Figure 9 is a side or general represent either of the forms of the invention utilising a wheeled platform.

Like reference numerals in the drawings indicate like or equivalent parts, and referring firstly to Figures 1 to 4, the construction illustrated includes a fixed base or supporting part II) on which is mounted a cabin II, said cabin housing the operating mechanism and being mounted for turning movement on the upper surface of the base I0, turning on the vertical spindle I2 with a ball race I3 concentric with the spindle I2 interposed between the underside of the cabin and the top of the platform. 1

The turning movement of the cabin on the vertical axis is obtained by means of a series of equally spaced holes I4 which series is arranged on an arc concentric with respect to the vertical turning axis of the cabin. The holes of the series are for engagement by the teeth of the pinion I5 driven by the shaft I6 as later described, whereby as the said pinion turns, the cabin turns about its vertical axis. I 1

A clockwork or spring motor I! is mountedin the cabin II on a horizontal axle I8. Theoperating mechanism is supported by the parallelside plates I9, I9, said mechanism including the axle I8, the main cog 20 and the gear train consisting of the pinions 2I, 22, 23, 24, 25, 2B, 21, and 28 arranged in coaxial pairs, the wheel 28 forming in combination with the pivoted member 29 an escapement which, controls the speed of rotation of the gear train. ,The lever 4| acts as brake;

on the line 1 view which may of the cam 30 during its full rotation. The end.

of the horizontal arm of the lever has a slot 36 therethrough in which a pin 31' on the CO5; 38: engages, said cog being carried by a spindle 39 and meshing with a cog 40 carried by. thespindlel6. at one side (Fig. 3) and has the pinion l5 mounted thereon the teeth of which pinion are shaped to engage in the arcuately arranged row of holes [4. Starting attheposition. shown in Figs; 1 and 4; with theaxlel8' rotating, the'cam. 3.6. during its rotation rocks the lever 32;.whichmovement through the slot and? pincoupling 3.6, 35?, turns the. cog 38' and thereby turns the pinion l5 through the cog 40. The rise of the cam' 30 is sufiicient to give a turning movement of the cabin of approximately 90, whereupon the: arm end 34 rideson the cam edge part' 3% which is arcuate with respect to the axis of rotation of the'cam so that the lever 32' is stationaryand consequently thecabin does n'ot turn until: the end 34 commences to rideon thefall of thesaid' cam. The movement of thejib arm 42 occurs whilst the cabin is stationary, saidjib arm movement being controlled by the cam 31 and link.- age. The jib-arm is pivoted by a pin 44' on the transverse axis-of the cabinbeing urged by the coil spring 45 around' the pin into its maximum up-swung position. The linkage comprises two arms 46, 4T, pivoted together at 48' with the. one arm 46 at its lower end loose. on the spindle 33, theother arm 4Tbeing pivoted to the one side of the-jib-arm. In the position shown in Figs. 1'

and 4, the arm 42 is lowered-to its maximum extent andas the cam 31 rotates; the pin on the arm 46 (which pin bears-on the edge-f cam 319 rides on thecam surface resulting inthe lifting of the jib arml- The pickup bucketSD-is connected to the jib arm by a cord 51 anchored atone end at 52, then passingaround the pulley'53, back and over the double grooved pulley'54, around the bucket pulley 55, back over thepulley- 54, and is anchored at its other end at 56. A second cord B-Tis con-- nected at one end to the-rear ofthe bucket, and

passes-over the pulley 581 and its other end is connected to the upper'end' of the lever- 58. Said lever 59 ispivot'ed in a-yolie-Bil fixed to themotor crossbar 61 and the inner face-of the gear 2%) has a pin 62' thereon. With this arrangement, for each revolution of'the axle I22 i. e. once every cycle of operations, the lever- 53 is rocked in counterclockwise direction Fig. 4 by the pin 62- so that the rear end of the bucket i's'rai'sed to tip said bucket.

The mechanismin the first embodiment shown is timedto operateas'follovvs:

Assuming the" partsare i'n the position shown in Figs. 1', 3= and 4', then the bucketisin its loading position. As the'axle l8 rotates, the jib arm first swings upwardly, under the action of the cam 34 and it's-associated: linkage, and the cam 30; throughitslever 3 2 and-gear train and arouate rack l4 turns the cabinthrough'approximate- The spindle l6 projects beyondtheplate [-9.-

' ward and back movement to the chassis.

4 ly 90 to the position shown in Fig. 2. It will be seen that the jib arm rises prior to the cabin turning movement i. e. into the position shown in broken lines. After the cabin has stopped turning, continued movement of the cam 3| results in movement of linkage 46, 41 to lower the jib arm, and when lowered, the pin 62 on the gear. wheel 20 has-.move'diintoa position to rock the lever 59; so raising 'therear' of the bucket or scoop and tipping same, the parts being in the position shown by full lines Fig. 2.

Referring now to the construction which is illustrated in Figs. 9, and 6, and in particular to the latter two figures, the cabin is mounted on a vertical axis for turning on the platform a which platform comprises a chassis structure mounted ontwo pairs of wheels 63, 63, and E4, 54, the rear pair 54 being driven to impart a for- The wheels may be coupledby an endless track or band. at" each; side. Thewgear. wheel 20. in this case' is;formed' on: its:one.face witha cam ring 65, andalso.mountedwithinthering and driven by the axle. lflcis'the; cabin turning cam 30. This latter-cam; iscoupledi through: the elbow arm 32a and? pin 3'40; to a.crank;66, theend of whichengages; in the: slot 3.6a, whereby onthe rocking of the arm, the arcuate. contrate gear wheel 6'! is turned, said gearJbeing coupled. to a cog E8'on a vertical spindle; 69. Beneath: the. cabin base is the; gear wheel. lilalso; mountedxon the spindle.

39, saidxwheelfldmeshing withtherack'llia concentric. with. respect to the vertical cabinmounting spindlelZi The. spindle l2'in;this;embodiment has a bevel wheel ll. onits: upper: end and a similar wheel 12 at'itsxlowerend,.which:wheel l2'meshes with the bevel wheel-13; keyed. to: the shaft. 6.4a.

The. drive to the bevelwheeli II. is through'the bevel wheel. M mounted. on the spindle 5 to which drive is imparted by. the cog 16' mounted onsaidspindle' ThezcamringfiE is utilised to control the drive'to' the cog 16, so that said cog canibe' stationary'(during.the major part of the'jib arm movement): or turn in one direction for forward. chassis movement, or turn in the opposite direction; for: rearward. chassis movement. This. reverse movement maybe imparted by'any suitablemeans suchas adog clutch mechanism, but preferably the movement is imparted by the pair of" pinions 11, Ha mounted on a cradle 18. freely'pivotedzonthespindle 15, the cradle: being rocked by the cam so that both pinions 1.7, Ila: can be. free from engagement with pinionsZZ, respectively in the gear train which in this case. mesh and are identical to travel: at. the same peripheral speed, or pinion 11 can. mesh with pinion 22 or (as shown in Fig. 6) pinion .ll'a meshes with pinion 24.

The coupling betweenithe cam ring and the cradle is through. a crankedi arm 79 having a pin 80' atiits' upper end'to engage the cam ring which arm 19 is also coupled to said cradle by the pin/8t on. the cradle and slot 82 in the arm end, the arm 79. being" pivoted to the plate l9 at 83. The said pin 80' isconstrained to follow the outward curves of the cam. track 35 to couple the drive. to, and 'uncouple the drive from the wheels, byv virtue firstly'of the path formed between said curve and thecam 30, and secondly by virtue of the path formed between the abutment 84 and the said curve. In this embodiment the gear train comprises the pinions 2|, 22, 24, 25, 26, 21 and 28, the speed being controlled by the escapement'29. It-will be clear that 'pinions 22 and 24 travel at the same speeds but in opposite directions.

The mechanism for operating the jib arm is conveniently the same as described with refer ence to the first embodiment, and in the position shown in Figs. 5 and 6, the drive is coupled to the rear wheels, the pin 80 being in the operative section between abutment 84 and cam track so that the platform is moving forwardly, until the pin 80 leaves the depressed cam part whereupon the drive to the wheels is broken. It will beunderstood that the drive to the wheels is coupled up only when the pin 80 is in the one or other of the two operative sections above defined, that is to say, the platform is stationary when the pin 80 rides on the two sections of the cam which are concentric with its center of rotation or plain sections. As the pin 80 commences to ride on its approaching first plain section, and durin the period it rides on this section, the jib arm is lowered by the cam and pin arrangement 3|, 49 and associated levers, as described with reference to the previous embodiment. The cabin remains stationary with the jib forwardly extending, when the said jib is moving, the cam 3| being located on its shaft [8 in suchan angular position that the jib arm rises before the pin 80 runs on its next operative cam part adjacent the larger radiussed part of cam 30. I

When the gear to the rear wheels is next coupled up, the structure moves rearwardly, un-

til the pin leaves theoperative cam part aforesaid. The cabin is now turned on its axis, as the pin 34a now leaves-the smaller radiussed part of the cam 3| and on or just before the cabin completes its movement aforesaid (the pin 34a now riding on the larger radiussed part of its cam 31!), the jib arm is lowered. In this case, at the completion of the lowering action the: scoop is tipped and the jib arm then rises, whereupon the cabin is returned as thepin 34 is now riding on its cam section from the larger radiussed part to the smaller radiussed part, and at or about the instant cabin stops and the pin 34a;commences to ride on its smaller radiussed part the pin 80 enters the operative cam part between the cam and the abutment 84.

It will be understood however, that the cam and actuating members may be arranged to produce any desired sequence of operations.

In the modification illustrated in Figs. 5, 7 and 8, an arrangement is shown wherein intermittent forward movement is imparted to the wheeled platform. In this case, the outer face of the gear 29 is formed as a cam track 85, and a rod 86, each end of which is bent as at 81, B8, issecured to the plate l9 by brackets 89, 89, whereby said rod can be turned on its axis. Theend 81 projects upwardly to engage the cam track 85, whilst the end 88 is coupled to the groove 90 formed by a boss between the flange 9! and the pinion 92. The said pinion is loose on the shaft 15, on which the bevel gear or pinion 14 is keyed, the coupling between pinions T4, 92 being made by the teeth 93, 93a. 4

When the arm end 8'! rides on theithick part of the cam rim, the pinion 92 is in the-position carries a pick-up bucket or'scoop, but it will be clear from the foregoing description with reference to the drawings that other forms of pick-up devices could equally well be used. Thus, a two part grab could be provided, the cord 51 being connected to the pivoted together parts so that the rocking of the lever'59 by the pin 62 moves the cord to open and close the grab at the appropriate points in the cycle of operations.

I claim:

1. Toy or model mechanical load lifting device comprising a base, a cabin pivoted on the base about a vertical axis, a jib arm fulcrumed on the cabin, a pick-up device carried by the jib arm, a power source on the'cabin, operable means on the cabin cooperating with the base and rotating the cabin on the base from one position to a second and back, second means driven by the power source and operating the first means for source and swinging the jib arm up and down While the cabin is in its first position and swinging the jib arm down and up while the cabin is in its second position, fourth means lowering the pick-up device relative to the jib arm during the upward swing thereof and raising the pickup device relative to the jib arm during the down swing thereof, and fifth means driven by the power source and lifting the rear end of the pick-up means when the jib arm is in lowered position in the second cabin-position.

2. A toy or-model mechanical load lifting device such as a grab or crane comprising a supporting platform, a cabin mounted on'a vertical pivot axis on said platform, a power source carried by said cabin, a jib arm carried by said cabin and mounted for swingingraising and lowering movement thereon, gearing between said power source and a drive between the cabin and platform for effeoting the turning of the cabin on its pivot axis,

cam mechanism actuated by the power source and operatively coupled to the said gearing to effect the turning of'the cabin from one position to a second position, and a second cam mechanism actuated by the said power source, which second mechanism is operatively coupled to the jib arm to efiect raising and lowering thereof, the two cam mechanisms being timed'so that the major portion of the jib movement to effect load pickup and dischargeis obtained when the cabin is in one or other of its stationary positions.

3. Toy or model mechanical load lifting device comprising a supporting platform, a cabin mounted on a vertical turning axis on said platform, a jib arm carried by said cabin ona horizontal pivot axis, a power source carried by the cabin, a main spindle in the cabin driven by said power source, a cam on said spindle, a linkage couplingsaid cam to a pinion, which pinion is coupledto a radial driving'rack on the platform, said cam having two operative sections for cabin turning movement from a pick up position to a discharge position, with non-operative sections therebetween, a jib arm operating cam on said spindle, a linkage coupling said jib arm operating cam to the jib arm, said jib arm operating cam having two operative sections for jib arm lowering and raising during non-cabin turning periods, with a pick up device carried by said jib arm.

4. Toy or model mechanical'load lifting device comprising a supporting platform, -a cabin' mounted on a vertical turning-axis on said platform, a jib arm carriedby said cabin on a horizontal pivot axis, a 'power'source carried by the.

cabin, a= mainspindle; in thez-cabin driven;by saidpowersource,- a-- cam' on: said spindle, a linkage coupling; said cam. to. a1pinion,;whicl'i pinion is coupledto aradia'l, driving rack-:onithe platform, saidicam having two operativesections for cabin turning movement. from a, pick up position to a discharge position, with :non-operative; sections therebetween, a jib. armoperating; cam on. said spindle, a linkage coupling said jib arm operating, cam to. they jib arm, said jib arm operating cam having; two. operativesections for'jib arm lowering, and raising during; non.cabinturning periods, witha pick up device. carriedby said jib arm andmeans driven by the. power source for operating; the: pick up deviceduring jib arm movement.

5. Toyormodel mechanicalload lifting device comprising; a supporting, platform, a cabin mounted on..a verticalturning axis orrsaid plat.

form, a jib arm carried by saidicabin. on a horizontal pivotaxis, a power source carried by the cabin, a. mainv spindle inv the: cabin driven by saidpower source,.a camon said spindle, a linkage coupling said cam to a pinion,which.pinion is coupled toa radial driving; rack onthe platform, said cam. having; two operative sections for cabin turningmovementfrom a pick up position to a discharge position, with non-operative-sections therebetween, a; jib arm operating cam, on said spindle, a linkagecoupling said'jib-arm operating cam to theijibarm, said.jib arm operating cam having two operative sections for jib arm lowering and raising during non-cabin turning periods, witha pick up devicecarried by said jib arm and means driven by the-power source for operating the pick up device during jib arm movement, said pick" upv operating means comprising a pulley guided cord connected at oneend to the pick up device and at the other end to the cabin, the power sourcecoupled to said cord by a linkage connected to the power source, which linkage is operated during stationary periods of the cabin.

6. A toy or model mechanical load lifting device such as a grab or crane comprising a supporting platform, a cabin. mounted on a vertical pivot axis on said platform, a power source carried by said cabin, a jib arm carried; by said cabin and mounted for swinging-raising and lowering movement thereon, gearing-between said power-source anda drive between the cabin and platform for effecting the turning of the cabin on its pivot axis, cam mechanismv actuated by the power. source and operatively coupled to the said gearing to effect the turning of the cabin from one position to a second position, and a second cam mechanism actuated by the said power source, which second mechanism is op-eratively coupled to the jib arm to effect raising and lowering thereof, the two cam mechanisms being timed so that the major portion of the jib movement to eifect load pick up and discharge is obtained when the cabinis in one or other of its stationary positions, a wheeledmounting for said platform, gearing between the power source, and the wheels for rotating same, and means actuated by the power source for interrupting the drive during cabin turning and jib arm movement.

7. Toy or modelmechanieal load lifting device as claimed in claim 6, in which the drive to the wheels is unidirectional.

8; Toy or model mechanical load lifting device as claimed in claim 6, in which the drive to the wheels is reciprocatory,

9. Toy or model mechanical load lifting device comprising: a. supporting" platform, a cabin mountedon avertical; turning axis on said platform, a jib arm carried by said cabin on-a,h0ri zontal pivot axis, a. power source carried by; the

cabin, a mainspindle inithe cabin driven by'said.

power, souree, a cam on said spindle, a linkage coupling said cam to a pinion, which pinion is coupledto aradial driving rack on the platform,

said cam havingtwo operative sections forcabin.

turning movement from a pick up positionto a discharge, position, with non-operative sections therebetween, a-jib, arm operating cam on said spindle,,a linkage couplingsaidjib arm operating cam to thejib. arm, said jib. arm operating cam having twooperative sections forjib arm lowering" and raising during non-cabin turning periods,

witha pick updevice carried. by said jib arm,

means driven. by thepowersource for operating the pick up device-during jib arm-movement, and, and a wheel, drive-control, cam on said main.

spindle, which; camiscoupled through. linkage tov an interrupting gear to the wheels.

10.. Toy or5model.mechanical'load'liftingdevice comprising a supporting platform,

form, a jib arm carried by said cabin on a horie zontal' pivot axis; a power source carriedby-the cabin, a main, spindle-in the cabindriven by said power source, a camon said spindle, a linkage coupling said cam to a pinion, which pinion is coupledjto a radial driving rack, on the platform, said cam havingtwov operativesections for cabin turning movement, from apick up position to a discharge position, with non-operative sections therebetween, a jib-arm operating cam on said.

spindle, a" linkage coupling-said jib arm operating cam to the jib-arm; said jib arm operating cam having two operative sections for-jib arm lowering and raising, during: non-cabin turning periods, with, a pickup device carriedby said jib arm, means driven by thepower source for operating the pick up device during jib arm movement, and a wheel-drive. control cam' on said mainspindle, which cam is coupled through linkage to an interrupting gear to the wheels, said interrupting drive comprising a clutch.

11.. Toy ortmodel mechanical loadliftingidevice comprising a supporting platform, a cabin mounted on a vertical turning axis on said platform, a jib armcarried by said cabin on a horizontal pivot axis, a power source carried by the cabin, a main'spindlein the cabin drivenby said powersouree, a cam on said spindle, alinkage coupling said cam to a pinion, which pinion is coupled to a radial driving rack on the platform, said cam having two operative sections for cabin turning movement from apick up position to a discharge position, with non-operative sections therebetween, a jib arm operating cam on said spindle, a linkage coupling said jib' arm operating cam to the jib arm, said jib arm operating cam having two operative sections for. jib arm lowering and raisingduring non-cabin turning periods, with-a pickup device carriedby said jib arm, means driven by the power source for operating the pick up device during jib arm movement, and a wheel drive control cam on saidv main spindle, which. cam iscoupled through linkage to an-interrupting gear to the wheels, said interrupting drive comprising a reverse gear having aneutral position, and the wheel drive control cam operates said gear to effect forward, reverse and stop of the platform.

12. Toy or model mechanical'load lifting device comprising; a supporting, platform, a cabin mounted ona vertical turning axis on saidplata cabin, mounted ona vertical turning axis on said plat-- form, a jib arm carried by said cabin on a horizontal pivot axis, a power source carried by the cabin, a main spindle in the cabin driven by said power source, a cam on said spindle, a linkage coupling said cam to a pinion, which pinion is coupled to a radial driving rack on the platform, said cam having two operative sections for cabin turning movement from a pick up position to a discharge position, with non-operative sections therebetween, a jib arm operating cam on said spindle, a linkage coup-ling said jib arm operating cam to the jib arm, said jib arm operating cam having two operative sections for jib arm lowering and raising during non-cabin turning periods, with a pick up device carried by said jib arm, means driven by the power source for operating the pick up device during jib arm movement, and a wheel drive control cam on said main spindle, which cam is coupled through linkage to an interrupting gear to the wheels, said interrupting drive comprising a reverse gear having a neutral position, and the wheel drive control cam operates said gear to effect forward, reverse and stop of the platform, said reverse drive comprising a pair of pinions carried by a rockable cradle to which movement is imparted by an arm actuated by the cam, said pinions meshing with a common pinion on a shaft coupled through bevel gears to the vertical shaft, the said cradle taking up one of three positions as determined by the cam, one said position meshing one pinion of the pair with a wheel in the gear train to turn the common pinion in one direction, a second position meshing the other pinion of the said pair with another oppositely rotating wheel in the gear train to turn the common pinion in the opposite direction, the third position breaking the mesh of both said pinions from the gear train.

13. Toy or model load lifting device comprising a wheeled platform, a cabin mounted on said platform on a vertical spindle, a power source carried by the cabin, gearing driven by said power source and coupled to the wheels, a cam driven by the power source and operatively coupled to a reverse and interrupting gear in the said gearing, a jib arm carried by the cabin, a cam driven by the power source and operatively coupled to the jib arm through mechanism for raising and lowering said jib arm, a cabin control cam driven by the power source and operatively coupled to a gear for effecting the turning of the cabin from a pick up position to a discharge position, said cam for controlling the reverse gear moving the cabin forwardly to the pick up position, said cam for the jib arm movement lowering the jib for the pick up operation in the forward position, said cam for controlling the reverse gear coupling up the said gear for reversal after pick up operation, said cabin control cam effecting cabin turning movement in the rearward position, the jib movement cam lowering the jib arm for discharge in the rearward position of the cabin and subsequently effecting the rising of the jib arm, said cabin control cam returning the cabin, in which position said gear controlling cam couples up the drive for forward movement of the platform.

JOHN BUCHANAN LOBB.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,020,802 Sauer Nov. 12, 1935 2,147,973 Ekbom et a1 Feb. 21, 1939 2,466,619 Stuckey et a1 Apr. 15, 1949 2,512,166 Merrill June 20, 1950

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