US3179438A - Toggle actuated caster arrangement - Google Patents

Description

April 20, 1965 P. M. FIELD 3,179,438

TOGGLE ACTUATED CASTER ARRANGEMENT Filed April 26, 1965 5 Sheets-Sheet 4 PH/L/P M'. F/E/ D INVENTOR.

April 20, 1965 P. M. FIELD TOGGLE ACTUATED CASTER ARRANGEMENT 5 Sheets-Sheet 5 Filed April 26, 1965 PHIL/P M. FIELD INVENT OR. W y

United States Patent Ofilice 3,179,438 Patented Apr. 20, 1965 3,179,438 TOG'GLE ACTUATED CASTER ARRANGEMENT Philip M. Field, Maplewood, NJ., assignor to Charles Beseler Company, East Orange, NJ., a partnership Filed Apr. 26, 1963, Ser. No. 275,829 13 Claims. (Cl. 280--43.14)

This invention relates to wheel-supported bodies, or the like, and more particularly to a foot-operated toggle arrangement for selectively elevating or lowering a pair of casters relative to the body thereby to allow for wheeling movement of the body over asurface or to retain the body in a firm, fixed position, respectively.

Relatively heavy bodies, such as table carriers, or the like, which must be moved about from place to place, generally are provided with a pair of casters which are free to swivel, thereby facilitating the movement of the body in a desired direction without the need of a separate steering mechanism. Inmanyinstances, it is also desired to have the body supportediu a firm, fixed position after the movement thereof to a desired position. Toward this end, various mechanical arrangements haveheretofore been provided for selectively lowering or elevating the casters relative to the body. These comprise various combinations of levers and latches, are often complex and generally inconvenient to operate.

In accordance with this invention, the casters are mounted on a spring-biased, toggle mechanism of simple construction and provided with a pair of pivotally-coupled levers, or pedals, arranged for convenient foot operation. The depression of one or the other of the levers causes the mechanism to swing to one or the other side of the spring axis, thereby effecting a positive positioning of the casters in either the elevated orlowered position. In the lowered position of the casters, the body is supported entirely on wheels and lcan be moved about freely. In the elevated position of the casters, the body rests upon a pair of fixed, non-caster wheels and on a pairof rigid feet. The mechanism is of simple, yet rugged, construction, is positive in operation and eliminates the need for separate latching means. Also, the foot-operated transfer of the casters, from one to the other position, is accomplished in a continuous, smooth motion, reducing to a minimum the possibility of jarring the body of carrier. This feature is important when the device is'used for carrying sensitive instruments, photographic equipment, and the like. i

An object of this invention is the provision of an 'arrangement operable to elevate or lower a pair of casters relative to a supported body.

An object of this invention is the provision of an arrangement for selectively lowering and elevating casters carried by a body, thereby respectively ,to permit Wheeling the body over a surface or to support the body in firm, `fixed position on the surface,

An object of this invention is the provision of afoot- A mechanism for raising and lowering the casters of a body,

said mechanism including a pair of foot-operable levers arranged so that the `depression of one lever positions the mechanism in a rst position wherein the casters are spaced from the surface on which the bodyis supported, and depression of theother lever positions the mechanism in a second position wherein the casters support the body on the surface.

These and otherobjects and advantages of the invention will become apparent from the following description when taken with the accompanying drawings, illustrating several embodiments thereof. It will be understood, however, that the drawings are for purposes of illustration and are not to be construed as defining the scope or limits of the invention, reference being had for the latter purpose to the claims appended hereto.

In thedrawings wherein like reference characters denote like parts in the several views:

FIGURE l is a side view of a wheel-supported body with a portion of the side wall broken away to show one position of the toggle mechanismi FIGURE 2 is a top view with the shelf removed `and the air cylinders omitted;

FIGURE 3 is similar to FIGURE l but showing the position of the toggle mechanism when the casters are in Vthe lowered position to support the body;

FIGURES 4-6 are fragmentary, isometric views showing the rear of the body withthe pedals in various relative positions;

FIGURE 7 is a fragmentary, isometric view showing the construction and arrangement of the operative components of the device;

FIGURE 8 is a fragmentary, isometric View showing a'modification` of the lever arms for effecting a braking action upon'the front wheels when the casters are in the elevated position;

FIGURE 9 is a fragmentary, crosssectional view showing the assembly of one of the front wheels and the modified lever arm;v and vFIGURE 10 is a fragmentary, isometric view showing another arrangement for braking Vthe front wheels.

Reference, n ow, is made to FIGURES 1 and 2 wherein `there are shown a generally rectangular body 10, made of sheet metal. The front end of the body is supported by two wheels 11, 11' which normally are freely rotatable about Vthe shaft 12, the latter being secured in position by the screws 13,-13'- threaded into tapped holes provided in the shaft for this purpose. The inner collars 14, 14' are secured inV position on the shaft by suitable set `screws whereby the axial clearance between the associated wheel andthe outer washers 1,5, 15' may be adjusted thereby to afford free rotation of the wheels withoperable arrangement for effecting movement of casters i carried by a body from an operative position wherein the casters support the body on a surface to an inoperative position wherein the ,casters are spaced from the surface.

An object f this invention is the provision of an improved arrangement for supporting a body on a surface, IwhichV arrangement comprises a pair of wheels carried by the bodyat one end, a pairi of casters and a pair of` feet carried by the body at the other end, a foot-operable mechanism for moving the casters to a first, fixed position wherein the casters support the body on the surface to a second, fixed position wherein the casters are elevated and the body rests upon the said feet, and braking means effective when the casters are in the said second position to restrain rotation of the wheels.

outside shake. A pair of metal. l lever arms 16, 16 have offset ends secured to the sides of the body by cooperating screws 17, 17 and nuts 18, 18', the arrangement being such that the arms are freely rotatable about a pivot axis passing `through the screws. The opposite ends of the lever arms are secured to a metal cross member 19, which cross member has secured thereto the vertical rods of the casters 20, 20. A shelf 21A divides the wheels and the toggle mechanism from the rest of the unit and serves as a` bottom for the useful portion of the body.

The rear wall of the body is provided with a generally rectangular opening 22 and the upper portion of the wall is curved inwardly, as indicated by the numeral 23, to form a stop for one of the foot-operable pedals, as

i Y will be described in detail hereinbelow. The bottom por- An object of this invention is the provision of a toggle t tion of the wall is turned inwardly forming a ledge 24 to which are secured a pair of rubber bottom supportsor feet 25, 25'. Y

The toggle mechanism comprises the foot-operable pedals 26 and 27 (each having upturned free ends, as

shown) and the coil-ed spring 28. The upper end of the spring is coiled about a fixed rod 29 carried by a fixed plate 30 which is secured to the body, whereas the lower end of the spring is coiled about a rod 31 carried by a bracket 32 which is secured to the cross bar 19. It is here pointed out that the toggle mechanism actually includes two coiled springs 28, 28 (as shown in FIGURE 2) and that the arrangement of the parts 4shown in FIG- URE 1 is somewhat diagrammatic for purposes of description. Suce to say, at this point,the pedal 26mcludes an integral arm pivotally supported by the xed Vrod 29, the pedal V27 includes an integralarm pivotally `supported by the rod 31, and each pedal includes integral arms pivotally secured together by rivet 33. Y Further, the pedal 27 is provided with an aperture 34 through which the free end of the pedal 26passes during operation of the toggle mechanism. l As shown in FIGURE l, the common pivot point o-f the mechanism (defined by the rivet 33) lies to the left of the center line of the coiled spring y28. In this position, the casters are in the elevated (inoperative) position, the rear of the body 1t) rests upon the iixed feet 25, 25', the pedal 27 is extended upwardly and the free end of the pedal 2 6 extends through the aperture 34 of the pedal 27. y

In orderto transfer the toggle mechanism to a second position wherein the casters are lowered, the operatorV places his foot `upon the upturnedend of the pedal 27 and presses the pedal downwardly, as shown by the arrow in FIGURE l. Such pedal pivots about the rod 31, which is carried by the bracket 32 that is secured to the pivot arms 16, 16. Inasmuch as the rod 29 is secured in fixed position relative to the body 10, the continued pivotal movement of the pedal 27 results ina simultaneous clockwise rotation of the lever arms and the movement of the common toggle joint 33 to the right. It is obvious that the movement of the joint 33 `to the right is accompanied by a stretching of the coiled spring 28 to the point 'where the common joint coincides with the spring axis.

. At this point, the rods 29 and 31 are spaced amaximum distance apart. Prior to reaching this point, the casters v20, engage the supporting surface'35, whereupon further downward depression of the pedal 27 results in the raising of the rear portion of the body 10.

This controlled foot pressure action by the operator is made self-evident by the design of the toggle mechanism and the construction of the two, foot-operable pedals. A considerable downward force must be applied to the pedal 26 (in FIGURE 3) to effect an initial movement of the toggle mechanism, since movement of the common joint 33 toward the spring axis can only be effected by increasing the spacing between the two rods 29, 31. This requires not only elongation of the spring, but a slight raising of the rear portionof the rbody 1li, since the casters rest upon the supporting surface 35. Once the downward movement of the pedal 26 has been effected to the point Y where the operators foot` rests upon the upturned ends of both Vpedals a further downward force is of no effect; as the pedals rotate/ in opposite directions. Such continued, opposite rotation of the pedals can only be brought about by releasing the foot pressure to permit the pedal 27 During the downward movement of the pedal 27, the i pedal 26 rotates in a counterclockwise direction about the rod 29. Once the common joint 33, of the toggle mechanism, moves to the right of the spring axis, the transfer movement is completed as `shown in FIGURE 3. The body is supported on the casters and the iixed feet 25, 25 are spaced from .the supporting surface. Further rotation of the pedals, under the ac-tion of the spring 28, is prevented'since the pedal 26 abuts against the inwardlycurled portion 23 of the rear wall of the body. In this position, the body may ybe wheeled to another position. Attention is directedy to the fact that the pedal 26 no extends beyond the wall of the body.

In order to transfer the mechanism to the original position, wherein the casters are elevated, the operator depresses the pedal 26 downwardly with his foot. This causes the common joint 33, of the mechanism, to move to the left, past the axis of the spring, and to the position shown in FIGURE l. As the pedal 26 is moved downwardly, the pedal 27 moves upwardly (that is, rotates in a lcounterclockwise direction about the rod 31). About half waythrough such reverse, pivotal movement of the two pedals, the'upturned end of the pedal 27 will strike the operators shoe. At this point, the toggle joint 33 has just passed to the left of the spring axis and the body 1i) is still supported on the casters. The spring now tends to pull the two rodsf29 and 31 toward each other which action, however, is counteracted by the foot pressure maintained against the pedal 27. By releasing the foot pressure gradually, the operator controls the Yfinal movementof the toggle mechanism whereby the casters are raised and the ybody is lowered, simultaneously.

to continue its upward movement, .during which time the free end of the pedal 26 has passed through the aperture 34 in the pedal 27. Such release of the foot pressure can be gradual to afford a smooth elevation-of the casters after the feet 25, 25 rest upon the supporting surface 35. Only a relative small force is required to prevent jarring of the body on the lifting stroke of the toggle mechanism to overswing the spring axis by 7-10 degrees, whereby the vertical movement of the body is very slight.

In general, after one or two operations of the pedals, the operator develops a feel for the mechanism whereby the transferof the toggle mechanism to one or the other position is accomplished in a smooth manner without jarring of the body. It is apparent that the operation of the Vpedal 27 (hereinafter referred to as the operating pedal) to lower the casters from the elevated position shown in FIGURE l to the lowered position kshown in FIGURE 3, presents only a small possibility of jarring the body. As the casters are lowered, they come to rest upon the supporting surface, after which the rear portion of the body must be raised. Operation of the pedal 26 (hereinafter referred to as the release pedal) to elevate the casters from the position shown in FIGURE 3 to the position shown in FIGURE 1 may result in slight jarring of the body by a carelessoperator. This may also occur if the operator deliberately or accidentally removed his foot from the pedals, suddenly, after his foot rested upon both pedals.' `To obviate this possibility, dashpots 36, 36' may be connected between the lever arms 16, 16' and a fixed surface ofthe body. Such dashpots are shown in a diagrammatic sense in the drawings to eliminate confusion. Those skilled in this art will understand that such dashpots preferably are connected .as close as possible between the extreme pivot points of the toggle mechanism for maximum damping action. l

Reference, now, is made to FIGURES 4-6 which are I fragmentary, isometric views taken from the rear of the unit. In FIGURE 4, the body is supported on the casters 20, in which position the release pedal 26 extends from the body over the operating pedal 27 (see, also, corresponding FIGURE 3). As described hereinbelow, pressing downwardly upon the release pedal requires a force sufficient to stretch the coiled springs of the toggle mechanism and to raise the body slightly. When the toggle mechanism just passes beyond its center point (spring axis) the two pedals occupy the relative positions shown in FIGURE 5, that is, the upturned ends of both levers are engaged by the operators shoe. At this point, the foot pressure gradually is released (the shoe is raised), whereby the pedal 27 Vmoves upwardly under the action of the stretched springs. -At the same time, the release pedal 26 moves downwardly through the aperture 34 in the pedal 27, as shown in FIGURE 6. This action continues until the pedals reach their extreme position and the body is supported on the fixed feet 25, 25', with the which reference now is made. Here are shown the casters 2t), 20 carried by the cross bar 19 secured across the endsof the lever arms 16, 16. The coiled springs 28, 28' are provided with hook ends disposed over the spaced rods 29 and 31, the lower rod 31 being carried by the generally vU-shaped bracket which is secured to the cross bar 19, and the upper rod 29 being carried by the bracket 3i) which is secured to the rear wallV of thebody 1t). The operating pedal 27, provided with the aperture 34, is a unitary, metal piece having one set of spaced arms pivotally mounted on the lower rod 31 and another set of spaced arms 41. Similarly, the release `pedal 26 has one set of spaced arms 42 pivotally mounted on the'upper rodA 29 and another set of spaced arms 43. The adjacently-disposed arms 41 and 43, of the respective pedals 27 and 26, are pivotally connected together by individual rivets 33, 33. VThese rivets are in axial alignment and form the common joint of the toggle mechanism, which joint moves from one to the other side of the plane of the spring axes upon operation of thepedals, as has already been described.

When the body is supported on the casters, it is in condition for wheeling movement to a desired position. When the body is supported 'on the fixed feet, it will remain in relatively iirrn, fixed position. However, when the body 1t) is a table supporting a photographic projector, itisdesirable to brake the front wheels thereby to prevent movement of the table even though the fixed feet are provided with rubber discs which engage the supporting surface. One arrangement for braking the front wheels,

when the casters are in elevated position, is shown in,

FIGURES 8 and 9.

Referring specifically to FIGURE 8, the lever arms 16a and 1617 correspond to the lever arms 16, 16 shown in FIGURES l-3. vThese arms are provided with oiset portions 45, providedwith aligned holes 50, 5 for accommodating the screws by means of which the arms are pivotally attached to the opposed side walls of the body. The free ends of the lever arms areprovided with openings 51, 51', each opening being of a somewhat'fan shape formed by two, intersecting holes of different diameters. The shaft, upon which the front wheels are mounted (see shaft 12 in FIGURE 2) passes through the lever arm openings 51, 51'. Inasrnuch as such shaft is in fixed position, relative to the body, pivotal movement of the lever arms about the axis x will change the location of the openings S1, 51 relative to thefront wheel shaft. Specically, when the casters are lowered, the front wheel shaft will pass through the relatively large, lowerportions of the opening 51, 51. Conversely, when the casters are elevated, the front wheel shaft will pass through the relatively smaller, upper portions of such openings.

The appropriate braking action will become apparent from a study of FIGURE 9. This is a fragmentary view showing the left front wheel 11, which normally is freely rotatable about the shaft 12, said shaft passing through an opening in the side wall 52, of the body, and being secured in position by the screw 13. Axial movement of the wheel, to the right, is restricted by the collar 14 which is secured to the shaft by a set screw 53. A bowed spring Washer S4 is disposed between the at hub of the wheel and the collar. The shaft 12 passes through the opening 51 of the cooperating lever arm 16a, said lever arm being spaced from the side wall 52 by a at washer 55. Disposed between the lever arm and the wheel hub is a braking washer 56 having the form of a truncated cone and preferably made of hard rubber. A portion of the braking washer at all times projects partially into the fanshaped opening 51. Thus, when the casters are in the lowered position, the end portion of the lever arm 16a, as shown in FIGURE 9, will be raised to its maximum position relative to the shaft 12. In this position, a portion of the braking washer 56 extends into the largest diameter portion of the opening 51 and, consequently, the Wheel is free to revolve about the shaft. However, when vti the casters are inthe fully elevated position, the end of the lever arm is lowered to its maximum position relative to the shaft,.thereby placing the smallest diameter portion of the opening 51 into a position concentric with the shaft 12. Such smaller diameter opening will accommodate less of the braking washer and, consequently, the washer is forced to move to the right along the shaft 12. This clamps the wheel hub between the braking washer and the spring washer 54, thereby preventing rotation of the wheel.

Another embodiment of` the `wheel braking` arrangement is shown in the fragmentary view of FIGURE 10.` Here, the free end of the lever arm 16a carries a brake shoe 57. Pivotal movement of the lever arm 1611about its axisx, moves the brake shoe into and out of engagement with the wheel, corresponding, respectively, to the elevated and lowered positions of the casters. The FIG- URE 10 arrangement is particularly adapted for use with wheels having rubber tires. 1

`Having now described the specific embodiments of the invention, it will be apparent that the toggle arrangement -for selectively lowering and elevating the casters is of rugged construction, convenient to operate and positive in action. This is accomplished without the -use of separate latching means `for retaining the casters in one or the other positions. The relatively large angular' deliection of the foot-operable pedals, to effect a transfer ofthe caster position, is desirable as it promotes easy, smooth operation. The spring-biased toggle mechanism also is of practical benet as it provides a desirable mechanical advantage for the raising of a heavy body. Further, the optional braking -feature requires no change in the basic toggle mechanism, which promotes economy of manufacture. While I have shown and described one construction of the toggle mechanism and two embodiments of the braking arrangement, Vthose skilled in this art will have no difficulty in makingvarious changes and modifications to adapt the broad features of the invention to specic applications. It is intended that such changes and modifications can be made without departing from the scope and spirit of the invention as recited in the `following claims.

I claim: t i l., An arrangement for selectively lowering and elevating casters carried by a body comprising,

(a) a pair of lever arms pivotally secured to the body for rotation about a common axis, (b) means securing the casters to the lever arms at points spaced from the lever arms pivot axis, (c) a spring-biased toggle mechanism connecting the lever arms to the body and operable between rst and second positions, said casters being respectively lowered and raised relative to the body when the mechanism is in the iirst and second positions, and

(d) foot-operable members for effecting a movement of the toggle mechanism from the one to the `other position. t

2. An arrangement for selectively lowering and elevating casters carried by a body comprising,

(a) a pair of spaced lever arms pivotally secured to the body,

(b) means securing the casters at corresponding ends of said lever arms,

(c) a iirst pedal member pivotally mounted for rotation about a iirst axis that is xed with respect to the body,

(d) a second pedal member pivotally mounted for rotation about a second axis that is xed relative to the lever arms, Y

(e) means pivotally connecting together the two -pedal members along a third axis intermediate of said first and second axes,

(f) means limiting the extent of pivotal movement of the two pedal members, and (g) spring means normally tending to reduce the spacing between the said rst and second axes, thereby providing a zone of instability when the third axis position, and rotation of the second pedal member lre- Y sults in a movement of said third axis to a fixed position to the other side of said straight'line land the casters are in the lowered position.

3. An arrangement for selectively lowering and elevating casters carried by a body comprising,

(a) a pair of spaced lever arms having corresponding ends pivotally secured to the body,`

(b) means securing the casters to the other ends of A. said lever arms,

(c) a first rod secured in iixed position relativeto the body,

(d) a second rod carried by the said lever arms,

(e) a rst foot-operable pedal member having arfirst set of spaced arms pivotally carried by said iirst rod and a second set of spaced arms,

(f) a second foot-operable pedal member having av first set of spaced arms pivotally carried by the said second rod and a secondv set of spaced arms, (g) spring means connected between the said first and second rods,` and (h) means pivotally connecting together the second sets of spaced arms of the two pedal members.

4. The invention as recited in claim 3, wherein a wall v of the body member is provided with an opening through which the said pedal members extend, and the second pedal member is provided with an aperture lthrough which the first pedal membergpasses as the pedal members are pivotally rotated yabout their respective rods.

5. 'The invention as recited in claim 3, including means damping the movement of the said lever arms in response Y to movement of one or the other of said pal members.

6. A body adapted for wheeling movement over aV surface comprising, Y s

(a) a pair of wheels normally freely rotatable about a shaft carried by the body at the front end thereof, (b) a pair of spaced `lever arms pivotally secured to the body andhaving free ends proximate to the rear Vend of the body, (c) a pair of casters,

(d means securing the casters to the free ends of said lever arms, v

(e) a vfirst rod carried by the body and a second parallel rod carried by the said lever arms,

(f) means forming an openingV in therear wall of the body, Y

(g). a rst pedal'member having a irst pair of spaced arms pivotally carried by said iirst rod, `a second set of spaced arms, 'and a central foot-operable portion extending through thesaid opening in the body wall,

(h) Va second pedal member having a rst set of spaced arms pivotally carried by said second rod, a second set of spaced arms matching the corresponding secondvpair of arms of the first pedal member, and a foot-operable portion extending through the said opening in the body wall, f

(i) coiled springs connected between corresponding ends of said rods, and l (j) means'pivotally connecting together the second set of spaced arms of theV pedal members at a point intermediate of the said two rods.

7. The invention .as recited in claim 6, wherein the foot-operable portion of theY second pedal member is provided with an aperture through whichthe similar portion of the first pedal member passes upon rotation of one or the other pedal members.

8. The invention as recited in claim 7, including stop means limiting the rotation of the pedal members to a predetermined extent. Y

9. The invention as recited in claim 7, including means damping the pivotal movement of said lever arms.

i0. The Vinvention as recited in claim 6, including braking means etective upon a predetermined pivotal movement of the lever arms to prevent rotation of the said wheels. -k

11. The invention as recited in claim 10,'wherein said brakingl means comprisesbrake shoes carried by the leverv arms, which shoes engage the wheel upon said predetermined movement of the lever arms.

12. The invention as recited in claim 10, wherein the thebraking means comprises,

(a) means forming aligned openings in the lever arms through which the said shaft passes, each opening Y being deined substantially by intersecting circles of different diameters,

(b) conical members carried ons-aid shaft adjacent to the associated lever arms, each conical member having a base portion adjacent the hub of the associated wheel and an apex extending intoV the opening in the associated lever arm; and

(c) means limiting the am'al movement of each wheel away from its associated lever arm.

13. An arrangement for selectively lowering andtelevating casters carried by a body comprising,

(a) spaced parallel lever arms carried by the body and rotatable about -a' common axis,

(b) means securing the 'casters to the lever arms at points spaced from said common axis,

(c) a spring-biased toggle mechanism connecting the lever arms to the body and operable between rst and second positions, said casters being respectively lowered and raised relative to the body when the mechanism is in the first and second positions, and (d) foot-operable members for effecting a movement of the toggle mechanism from the oneto the other position. l

Reereneesited by the Examiner UNITED STATES `PATENTS 2,843,392 7/58 Simpkins a ZSC-43.14

PHILrP ARNOLD, PrfmaryExaml-nevr.

Claims (1)

1. AN ARRANGEMENT FOR SELECTIVELY LOWERING AND ELEVATING CASTERS CARRIED BY A BODY COMPRISING, (A) A PAIR OF LEVER ARMS PIVOTALLY SECURED TO THE BODY FOR ROTATION ABOUT A COMMON AXIS, (B) MEANS SECURING THE CASTERS TO THE LEVER ARMS AT POINTS SPACED FROM THE LEVER ARMS PIVOT AXIS, (C) A SPRING-BIASED TOGGLE MECHANISM CONNECTING THE LEVER ARMS TO THE BODY AND OPERABLE BETWEEN FIRST AND SECOND POSITIONS, SAID CASTERS BEING RESPECTIVELY LOWERED AND RAISED RELATIVE TO THE BODY WHEN THE MECHANISM IS IN THE FIRST AND SECOND POSITIONS, AND (D) FOOT-OPERABLE MEMBERS FOR EFFECTING A MOVEMENT OF THE TOGGLE MECHANISM FROM THE ONE OF THE OTHER POSITION.

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