MXPA00003553A - Steerable load-carrying assemblies - Google Patents

Abstract

A moveable load-carrying assembly including a chassis (1) having a plurality of wheels (6) arranged as a first wheel set and a second wheel set, each wheel (6) being rotatable and swivellable relative to the chassis (1);the wheels (6) of the first wheel set being connected by a first linkage (21), and the wheels (6) of the second wheel set being connected by a second linkage (22);and wherein one of the wheels (6) of the second wheel set is linked to the opposite one of the wheels (6) of the first wheel set by a link (11) such that when one of the wheels (6) of the first wheel set is swivelled in one direction relative to the chassis (1), all the wheels (6) of the first wheel set swivel in that direction in unison, and all the wheels (6) of the second wheel set swivel in the opposite direction in unison. Means are included to provide three distinct modes of operation for a wheel set, the modes corresponding to straight-line travel, fully-steerable travel and a braking mode. The assembly also includes an apparatus for returning the steerable wheels to a straight-line position, comprising a first member (203) associated with a tie rod (202) operably connected to one or more steerable wheels, at least one further member (205, 206) pivotably associated with a fixed chassis member (201) and a resilient means (209) associated with the further member.

Description

CARRIER SET DECARGADE MANUAL HANDLING Field of the Invention The present invention relates to a manually operated movable load carrying assembly and relates particularly, although not exclusively, to a movable load carrying assembly that can be driven. The present invention also includes a centralizing mechanism to be used with such load bearing assemblies to assist in driving the entire assembly.

Definitions In the course of the present description reference will be made to a tub for carrying babies, a wheelchair for carrying babies, invalids and similar loads *? * It should be understood that such preferred embodiments are offered with a mere character of example and not should be considered co or being limited to ta '< < > Applications. By the way, the present invention will be suitable to be us > In any set intended to march carried by human effort rather than by a driving force, including, for example, cars of all sizes. We are used to make purchases in markets, toy cars, cars to carry boats, cats with wheels for vehicles, wheelchairs, branches! Hospitals, hospital beds mounted on a base provided with? u «« la- "work platforms, bookshelfs used in libraries, and other similar vehicles that have a number of common wheels and / or pivoting wheels., ot > E wheels that rotate on a horizontal axis carried by a support carried to its v * »? rotating by a fixed vertical axis. In the course of all this description the reference to a wheel or vains and they should be interpreted as including the reference to one or several pivoting wheels or a wheel acting as such. In the course of all this description the reference to a chnsir »Should be interpreted as including the reference to a frame Fundamentals of the Invention According to the already known provisions, baby cars have wheels that rotate on fixed axes. This makes its use arduous in an undue and undesirable way. For example, it may happen that baby corks provided with wheels that rotate on fixed axes have a radius of rotation pi? J. very large, which obviously imposes limitations and consequences In addition, when making a turn it can happen that the wheels are dragged laterally, which increases the wear. According to the known arrangements, movable assemblies of the above-mentioned type can be said to belong to one of the following three forms: (i) a first form, in which the four wheels rotate tedas about a fixed axis and can not be driven from no mode (for example, traditional forms of baby cars); (ii) a second form (for example, chairs with baby wheels and similar applications) in which the rear wheels rotate on fixed axes, while the front wheels are pivoting; or (iii) and a third way in which the four wheels are all independently pivoting (for example, shopping carts in the market). It has been found in practice that each of these three forms offers a number of advantages that make them suitable for certain uses, but suffer from disadvantages that limit the possibility of assigning them to all uses. When the four wheels rotate all on fixed axes (the first form), an advantage is that the wheels can have a fairly large diameter, which allows the assembly to move more easily on uneven terrain. Another advantage is that such sets sor? suitable for traveling along paths where it is not necessary for the user to concentrate on driving during normal driving, and should do so only when a change of direction is needed. Therefore, when larger diameter wheels are used in sets whose wheels rotate on fixed axes, walking is more comfortable for the occupant, which is an important result when the occupant can be a baby. It has also been found that assemblies whose wheels rotate on fixed axes can march along a slope or an undulating terrain without the user having to exert excessive effort to maintain the assembly in the desired direction., except when a change of address is required. Such assemblies provided with wheels that rotate on fixed axes suffer from the disadvantage that it is difficult to effect a change of direction. Two commonly used methods consist of either pushing down the handles to raise the front wheels and moving them away from the ground, and moving the handles angularly in the horizontal plane, to orient the assembly in the desired new direction of travel; or raise the handles so that the rear wheels lift off the ground and move the handles angularly in the horizontal plane to obtain the desired new direction of travel. Alternatives require both skill and the application of a ^ s-u r. considerable. Other disadvantages of such sets of wheels that rotate on which s * -i r > They include excessive wear of the weapon components or structure, which can result in a deformation of the frame. The effort required by the user can be excessive As testiltado. the type assemblies provided with wheels that rotate over fixed and unproved eyes are unsuitable for applications such as shopping carts in markets, where frequent air changes are required within spaces that are normally reduced. The second form refers to the assembly whose rear wheels rotate on fixed axes, while its front wheels are pivotanios. The joint units have the advantage that they are more easily handled, in terms of both space and effort. However, this form has the disadvantage that it is necessary to use small diameter wheels, to allow the pivotant c to make the support that carries the axle on which the front wheels rotate; of 360 ° since such wheels. They are generally mounted under the assembly or must produce there the pivoting offer. The use of such wheels of small diameter h 'or that * < It is more difficult for the assembly to travel on uneven surfaces, or abrupt, and also makes the march much less comfortable for the occupant when comparing with sets whose wheels have a large diameter and rotate on fixed axes. In addition, the front wheels are pivoting or function as such. As a result, they are not linked to each other and individually accompany the terrain, which can cause the pivoting front wheels to be oriented in different directions, making it extremely difficult for the user to maintain control, especially when the assembly is running on a Sloping surface With such assemblies, when walking on a sloping or uneven surface, it is necessary that the user concentrates on the handling and has to make a great effort to keep the assembly oriented in the desired direction. The sets whose four wheels are all independently pivoting - the third form - have the advantages of being very manageable, capable of making turns with a turning radius equal to their own lopgilud; And they can be used with the same ease and efficiency when pushed and / or pulled in one or the other direction. Such assemblies have therefore proved to be particularly suitable for use as shopping trolleys, wheelchairs for babies, and similar applications. Such assemblies also suffer from a number of disadvantages. First, they lend themselves better to use on horizontal and flat surfaces, making it difficult to maintain control when the whole must march down a slope. In addition, since the castors can be carried by supports that can take a complete 360 ° turn, the sets of this shape can only be made with small diameter wheels, which again makes the march less comfortable for e! occupant and even if the wheels are locked in the position where they allow only forward movement. Because the four wheels are all pivoting, they can all work independently, especially when the assembly must run on uneven surfaces. Because they are not linked, the wheels can all point in different directions at any given time. As a result, the control of the whole can be difficult. In the case of load bearing assemblies of known type there is a tendency that the direction of movement can be easily altered. A variety of means have been employed with the intent to provide an improved driving possibility, but without success. The present invention aims to solve the problems and disadvantages of the already known assemblies by providing a mechanism by means of which the pivoting wheels of a set are retained in a position that allows the straight forward movement, and that ac. Te a to make the caster wheels return to the position that corresponds to the straight gear of the set. Preferably, this effect is independent of the degree to which the caster wheels are forced to deviate due to variations in terrain and other factors. ? In still another aspect, the present invention preferably acts to prevent any tendency that the assembly may show to deviate from the position corresponding to the forward forward march, and compensate for this tendency of the assembly to proceed in any manner other than a straight line. .

Provisions are Well-known The development of reliable arrangements for carrying load-bearing assemblies of the type of the present invention is very scarce. For example on c.? PCT / GB96 / 00687 discloses a cart, such as used for shopping in a batch, which has a wheel pivoting on a corner. The caster wheels are arranged so that there is a driving wheel (rear) and a driven wheel (front) An endless gearing mechanism allows the driving wheel on one side to drive the driven wheel on that side, so that when the driving wheel makes a turn in one direction, the driven wheel makes the turn in the opposite direction. embargo. there is no link between the wheels on one side and the wheels on the other side Polo, the wheels on one side can make a turn to the right (rear rundas) and to the left (front wheel), while the wheels «I read another side can make a left turn (rear wheel) and to the right (front wheel) This would destroy the whole exercise. On the other hand, it is only valid in the case of castors which are arranged immediately below the frame and is not applicable to any other wheel shape, or to any other form of product.

On the other hand, in the North American patents that carry the numbers 4.348.0333 and 4.405.140 a sledge is dislodged that can be driven and whose four skids are linked to be able to be directed However, the mechanism comprises a complicated arrangement that requires numerous parts , accompanied by cables and link bars. In addition, it is intended to be managed from the inside and not from the outside. This is a fundamental difference since when the operation is carried out from within there is an occupant who can direct the apparatus and is not destined to be handled by external forces. With a device such as a baby car or a chair with wheels also for babies, the conduction is carried out from the outside and is therefore destined to be controlled by external forces. It should be added that with devices such as the ones just mentioned, the same, as inherently natural, are not intended to be handled by internal forces since otherwise a child or a very restless baby could control the direction of travel of the car or of the chair with wheels, which is totally opposite to what is required.

COMPENDIUM OF THE INVENTION. According to a first aspect of the present invention there is provided a movable load carrying assembly including a chassis provided with a plurality of wheels that are arranged as a first set of wheels and a second set of wheels, each wheel being pivotable and pivotable of the chassis; the wheels of the first set of wheels being connected by means of a first link, and the wheels of the second set connected by means of a second link; and one of the wheels of the second set of wheels is linked with the opposite of the wheels of the first set by means of a link, so that when one of the wheels of the first set moves angularly or pivots in one direction with respect to the chassis, all the wheels of the first set pivot in that direction in unison, while the wheels of the second set pivot in unison in the opposite direction. v Preferably, there are two wheels in the front set of wheels. More preferably, there are two wheels in the rear wheel set. Advantageously, the chassis has a front transverse piece and a rear transverse piece. Most advantageously, the front crosspiece constitutes the front link. In addition, the posterior crosspiece may comprise the posterior link. Preferably, the link is a rod or rod connected angularly movably to one of the front wheels and to which it occupies the diagonally opposite position of the rear wheels. According to another aspect of the present invention there is provided a movable load carrying assembly in which means are included to provide three different operating modes for the rear play of wheels, the modes corresponding to the straight-line running (either forward or backwards), the fully driven gear (also either forward or backward) and a brake or wheel-lock mode. According to another aspect of the present invention is provided an apparatus for controlling the direction of travel of an assembly that can be driven including the apparatus- (i) a first part associated with a link rod connected to one or more of the pivoting wheels of the assembly; (ii) at least one other part associated with a fixed part of the chassis, said to the monkeys another part can selectively move angularly with respect to the fixed part of the chassis, "-.e.ro respective extreme positions, of which there is a non-ooorati and another operative, and (iii) elastic means associated with said monkeys another foot / n. the arrangement being such that, during use, when the driving wheels of said assembly undergo a steering field, the first piece and said at least one additional piece come in contact, so that the clastic means act to cause said to the monkeys another piece returns to its non-operative position, thus correcting the conduction of said set Description of the Disorders In order that the invention may be more clearly understood and implemented, preferred embodiments of movable load-carrying assemblies constructed in accordance with the present invention will be described below, the description being only a non-limiting example. and should be interpreted with reference to the accompanying drawings, in which: Figure 1 is a plan view of a first embodiment of a chassis of a movable load carrying assembly. Figure 2 is a view similar to Figure 1, showing the assembly of Figure 1 in its most suitable configuration for making a turn when all wheels are conductive. Figure 3 is the view of a cut taken along and in the direction indicated by arrows 3-3 of Figure 1. Figure 4 is a view similar to Figure 3 showing an alternative embodiment of a set constructed of According to the present invention Figure 5 is a partial plan view of the alternative embodiment of Figure 4. Figure 6 is a plan view of the embodiment of Figures 4 and 5, when the assembly is in the running mode forward in a straight line. Figure 7 is a view similar to Figure 6, but when the assembly makes a leftward turn. Figure 8 is a side view of one of the rear wheels of the assembly shown in Figures 4 to 7, when it is in the locking configuration, in which all the wheels are fixed and have any pivotal movement impeded, while the general arrangement acts in the conventional manner. Figure 9 is a view similar to Figure 8, showing a rear wheel of the alternative embodiment of Figure 4 in a second configuration, in which all wheels can describe pivoting movements. Figure 10 is a similar view of Figures 8 and 9 but showing the rear wheels with a third configuration, in which they are in a braking mode. Figure 11 is a view taken along and in the direction of the arrows 11-11 of Figure 10. Figure 12 is an elevational view of an assembly constructed in accordance with the present invention, incorporating the alternative embodiment of Figures 4 to 11. Figure 13 is a partial rear elevational view. of another embodiment of the present invention incorporating a centralizing mechanism. Finally, Figure 14 is a view similar to Figure 13 showing an alternative form of a centralizing device or mechanism constructed in accordance with the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS Now, following the consideration of FIGS. 1 to 3, a chassis constituted by an arrangement comprising a front transverse piece 2 and a rear transverse piece 3, which are connected with respective longitudinal pieces 4, is illustrated therein. The parts 2, 3 and 4 constitute the chassis 1 and are connected to each other in any known manner, for example by means of welds, bolts, rivets, etc., to provide a substantially rigid chassis 1. As shown in Figure 3, the pieces 4 comprise an elongated piece having a longitudinal portion 4b, and. extended from the rear end thereof, a curved portion 4a. and during use, the latter is adapted to receive and preferably removably refilled a collapsed assembly C. cue in turn is adapted to cooperate with load carrying means. In the vicinity of each end of each of the fransvet pieces. the 2 and 3 are mounted wheel assemblies 5. The wheel assemblies are formed by a wheel 6, a short shaft 7 on which the wheel G is mounted in a rotary manner, a pivot shaft 8 fixedly connected to the respective transverse pieces 2 and 3. and a support 9 mounted in an angularly movable manner on the pivot axis 8, preferably by the use of bearings or other means of appropriate type. The support 9 is rotatably carried by the pivot shaft 8 but disposed removably by the use of a key n other similar means TI short axis 7 is associated with the support 9 in such a way as to be substantially square with respect to the short axis 0 The wheels 6 can describe a rotary movement around their respective axis 7. They also have a pivotal relationship with the chassis 1 and around the respective pivot axis 8. In an alternative embodiment (not shown) a set formed by two wheels placed side by side, each wheel mounted rotatably in a respective free end of a short axis, the assembly being carried by a support and a key, to describe a pivoting movement with respect to the chassis 1. One of the front wheels 6 is connected, by means of a suitable link 1, to the rear wheel 6 on the opposite side. The front wheels 6 are linked together, in any suitable manner, and the same happens with the rear wheels 6. The final result of such arrangement is that the four wheels 6 are all steerable, the pairs of front and rear wheels being respectively movable in opposite directions. Turning next to the consideration of FIGS. 1 and 2, associated with each support 9 and extended at an angle therewith is a clamping piece 20. The clamping pieces 20 preferably have a boomerang-like shape, so that the front portion 20 a thereof can, if desired, make contact with the longitudinal part 4 before the wheel 6 makes contact with it, acting to limit the pivoting effect of the wheels 6 with respect to the chassis 1. The associated clamping pieces 20 with the rear wheels 6 are connected to each other by means of a rear link 21, and the fastening parts 20 associated with the front wheels 6 are connected to each other by means of a front link 22. One of the rear wheels 6, and one of the rear wheels 6, the front wheels 6 on the other side and opposite diagonally have an additional intermediate part associated with them 23, secured to the support 9 and extending at an angle both to the support 9 and to the clamping piece 20. The two additional intermediate pieces 23 are connected to each other by means of the link 11, so that when the rear wheels 6 they are moved angularly in a given direction around their pivot axes 8, the front wheels 6 move angularly in the opposite direction, around their respective pivot axes 8. In this way the possibility of fully directing the direction of travel of the general chassis 1 and the joint wheel assemblies 5. The assembly is such that each wheel 6 is subjected to a pivot type effect or functions as such. "A body to be installed on the chassis 1 is preferably secured to the front links 22 at points a (figure 1), and preferably secured in an angularly movable manner to the rear at point b (figure 3). In this way the body can be used to control the direction of travel of the front wheels 6 acting directly on the front link 22. thus directing the movement of the corresponding wheels 6. Turning now to figures 4 to 12 of the drawings, illustrates therein an alternative embodiment of a movable load carrying assembly. The reference numerals used to describe said alternative embodiment are the same as those used with the embodiment of figures 1 to 3. The alternative embodiment includes a chassis 1 formed by a piece front crosspiece 7. urine rear crosspiece 3, and cooperating longitudinal pieces? The various parts 2, 3 and 4 constituting the chassis 1 are connected if in any known manner, for example by welding, screws rivets, etc. to provide a substantially rigid structure. There may be two front cross pieces 2. mounted one above the other; and two transverse pieces 3, also mounted one above the other. The longitudinal pieces 4 extend between them I?. The actual configuration of the chassis 1 is an essential part of the invention. One of the transverse parts is mounted at each end of the caria. '> and l-, or in the vicinity of such extremes, there are sets of medas f > The wheel assemblies 5 comprise a pivoting wheel 6. a short shaft 7 on which the wheel G is rotatably mounted. a pivot shaft 8 connected tio. way to the pairs of transverse pieces 2 and 3, and which extends between the mrcmns. and a support 9 mounted in an angularly movable manner on the ptvote shaft 8. preferably with the aid of bearings or other means of appropriate type The supports 9 are rotatably carried by the pivot shaft 6 but are disposed therein in a removable manner. . The short axis 7 is associated with the support 9 so as to extend substantially square with respect to the pivot axis 8. As a result, the wheel assemblies 5 have a ptvote effect, being able to move angularly with respect to the chassis 1. One of the wheels front 6 is connected, by means of a suitable link 11, with the rear wheel 6 on the opposite side. The front wheels 6 are connected to each other in any suitable manner, and the rear wheels 6 are also connected to each other. Preferably, the support 9 of each set of front wheels 5 is fixedly pivotably connected to another link means, which has the shape of a rod or other similar element extended transversely with respect to the chassis 1. In an analogous manner, the sets of Rear wheels 5 are linked in a fixed but prvotantes way, by means of another transversal piece or link. The final result of such an arrangement is that all four wheels can all be steered. In the same manner as in the embodiment of FIGS. 1 to 3, the support 9 means that at least one of each of the sets 5 of front wheels and rear wheels has an additional intermediate piece associated with it., which extends from said assemblies forming an angle. The additional pieces 23, of the front and rear wheels of the opposite sides. they are connected to each other by means of the link 11. The fastening pieces 20 of the support 9 of the front wheels 6 are connected by means of a front link 22, to allow the front wheels to be moved angularly in unison with respect to the chassis 1. similarly, the rear wheels 6 are connected to each other by means of a rear link 21, so that the rear wheels 6 can also be moved angularly in unison. The end result is that when the rear wheels 6 are pivoted or angularly moved in a given direction relative to the chassis around their respective pivot axes 8, the front wheels 6 move angularly in the opposite direction. If desired, in the case of this embodiment, the cross pieces 2 and 3 can be combined into a central transverse piece, imparting to the chassis 1 a shape approximately similar to a letter H. As an alternative, the transverse pieces 2 and 3 they can be suppressed, replaced by a wire basket 29 or other similar structure, which in a fixed and / or removable manner is installed between the longitudinal pieces 4, in which case the basket 29 reinforces the structural strength of the chassis 1, and can be considered as part of the chassis 1. In the embodiments illustrated in Figures 4 to 10, the chassis 1 and associated wheels 6 are adapted to be placed in one of three modes of operation, including: (i) a first mode, in the that the wheels 6 can be locked in the direction but they are still rotating, facilitating the straight line movement, both forward and backward; (ii) a second mode in which the wheels 6 can be steered, both rotating around their respective short axes 7. and angularly movable about their respective pivot axes 8; and (iii) a third mode in which the wheels 6 are locked and have rotation impeded With particular reference to figures 8 to 11. the three operating modes are illustrated therein. Mounted fixedly to the monkeys is one of the rear pivot shafts 8 there is a locking piece 30 extended longitudinally outwards. Associated with the holding part 20, which is now part of the support 9 and which belongs to each rear wheel 6, there are respective lever parts 31, which are mounted angularly on them, and each lever part 31 is at its connected to an adjacent end of a rear link piece extending transversely to the chassis 1. The lever part 31 is angularly secured in the clamping piece 20 with the aid of any suitable means, such as for example a pin 33. A bolt 34 extends from the lever piece 31 substantially in squaring relation thereto, and cooperates with the rear end portion of the clamping piece 20 forming a cam follower type arrangement. Lever 31 is selectively movable in the respective Figures 8, 9 and 10, corposponding each position to the three operating modes. The application of a force on the rear link piece 21, such as for example that exerted by the foot of a user, can impart movement to the assembly formed by the rear link piece 21 and the corresponding lever parts 31, with that the set is moved to the desired position to obtain the desired mode of operation. When it is in the position shown in figure 8, the lever part 31 makes contact with the locking part 30, thus preventing the pivoting movement of the rear wheels 6. and in turn the movement of the linked front wheels 6, but without stop allowing rotation of the same wheels In this way, the wheels 6 are in a position that allows forward movement in a straight line. When they are moved to the position shown in figure 9, the wheels 6 are all rotary, and also they can be moved angularly, so that the whole assembly can be directed as explained antopormente When the lever part is moved to the position shown in figure 10, the bolt 34 makes contact with the cavity formed between projections 35 extended inwards and arranged around the hub 36 of the rear wheels 6, to prevent rotation of said rear wheels. Turning next to the consideration of Figure 12, there is illustrated therein a framework adapted to receive, and detach therein releasably, means suitable for containing a load, such as for example a tray or other similar element, a cradle , etc. The disposition, ta! as illustrated, it is adapted, in any known manner, such as, for example, with the aid of plug-in spikes, to be fixedly or detachably connected to a set provided with wheels, which can be directed and which is of the type described above. If desired, the locking piece 30 can be incorporated in a curved portion 4a of the longitudinal piece 4, so that the bolt 34 can be meshed in a suitable groove or recess (not shown) formed in the curved portion 4a. When compared to known assemblies, the one proposed by the present invention has been shown to exhibit important advantages. The wheels are all linked mechanically, and can be used either in the fixed wheel modes or fully steerable wheels, allows to take advantage of all the advantages of a set of fixed wheels, but if the disadvantages of them, such as it was mentioned above in the present description. Furthermore, the advantages of assemblies whose four wheels can be steered, without the disadvantages, are evident. The same can be said when the assembly of the present invention is compared with known assemblies that employ four separate sets of pivoting wheels.

Further, due to the fact that the wheels 6 are outside the periphery of the chassis 1, in the diameter of the wheel 6 there is no upper or lower limit, so that large diameter wheels 6 can be used (to provide a comfortable ride) and being able at the same time to be directed in the same way, and substantially to the same extent, as in the case where wheels of smaller diameters are used. With reference to the embodiment of Figure 13, it should be appreciated that it is adapted to be arranged between a fixed bar or similar piece 201, which constitutes the side pieces of the frame of a chassis of a baby car. wheeled baby seats, cars, and similar vehicles, and a movable bar or brace 202 extending laterally between baby car steer wheels, baby wheelchairs, cars, or similar vehicles. The fixed part 202 is movable in the direction indicated by the arrows (see Figure 13) in response to the pivoting movement of the wheels of the assembly, such movement of the wheels may be caused for a variety of reasons or due to a number of factors A piece 203 is secured, in any known manner, for example by welding, to the movable part 202, and is adapted to extend substantially, forming a square therewith. The piece 203 may take the form of a rod-like piece and carrying a rotating element, such as for example a roller 204. appropriately disposed at the free end thereof. Extending perpendicularly from the fixed chassis piece 201. in the direction of the moveable part 202. there are two pieces 205 and 206, spaced apart. substantially straight, and each of which is angularly movable in the direction indicated by the arrows, and with respect to the fixed piece 201. Such angular movement can be obtained in any known manner, for example by articulating the pieces 205 and 206 on bolts 207 secured to the fixed piece 201. Also extended substantially square from the fixed piece, and disposed between the spaced pieces 205 and 206. there are spacer means 208 for maintaining the spacing between them and having the shape of a projection attached to the fine part 201, according to any known manner, also, for example, by means of a weld. The pieces 201 and 206 are connected to the higher ends thereof or in the vicinity of such ends with the aid of an elastic piece 209 of any known type, such as for example a spring. The operating principle of the centralization mechanism constructed in accordance with the embodiment of Figure 13 is that when the link piece 202 is moved either to the left or to the right, in response to a change of direction of the wheels of the As a result, such pieces 205 or 203 move in the direction indicated by the arrow, going down in the direction toward the fixed piece of chassis 201 and overcoming. the pressure exerted by the elastic means 209. The elastic means 209 work to try to move the piece 203 and the attachments means of rollers 204 in order to make them return to the position shown in figure 13, in which they are arranged between the free ends of the opposing pieces 205 and 206. but not in contact with them. Therefore, the link piece 202 is forced to move in the opposite direction, thereby tending to straighten the wheels of the assembly to bring them to the position of the straight line forward travel. Therefore, as will be appreciated, the mechanism acts to compensate for any tendency of the assembly to deviate from a direction other than straight line running, and also to return the assembly to the forward running position in a straight line after that has made the turn.

The pieces 205 and 206 are provided with respective notches 210, in the form of "V" which tend to apply an uneven pressure on the roller means 204 as it moves to leave the central position illustrated. Because only one spring 209 is used to fulfill the centralization function, independently of the direction of movement of the link piece 202, the arrangement operates in a simple and at the same time effective manner. For example, there is no need to choose springs that have the same degree of elasticity, as would be the case when a single spring should be associated with each link piece 205 and 206. because in the present arrangement the same force is applied in both directions of travel. In the case of the embodiment of Figure 13, as soon as the link piece 202 is moved away from the position shown, which corresponds to the movement of the assembly forward and in a straight line, the spring 209 acts to attempt the movement of the link piece 202 to make it return to such a position, thus recovering the forward movement in a straight line direction. The more the piece 203 moves away from the illustrated position, due to variations in the ground or the reduced dimension of the turning radius, the greater the pressure of the spring acting to move the piece and make it return to the illustrated position.

The embodiment of figure 14 shows with full lines the arrangement designed to direct the assembly so that it runs in a straight line. The dashed lines are intended to illustrate what happens when the set is affected in any way that makes it go in a direction other than the straight forward march. In a manner similar to that described with reference to the embodiment of Figure 13, the alternative centralization mechanism of Figure 14 is adapted to be arranged between the fixed bar or similar link piece 301. which constitutes one of the side pieces of the car chassis for babies, wheelchair for babies, cars, or similar vehicles; and a movable link bar 302, laterally extended between steerable wheels of the aforementioned vehicles. "A piece 303 is secured in any known manner, for exa by welding, to the link piece 302 and is adapted to extend substantially squarely therefrom. The piece 303 preferably takes the form of a piece similar to a rod carrying rotary means, in the form of a roller marked in conjunction with the reference number 304, appropriately disposed in any known manner at the free end thereof. Secured to the fixed part 301 and adapted to be angularly moved relative thereto, there are two bolt pieces 305 and 306, which are angularly movable with respect to the fixed part 301 in the directions fixed by the arrows, according to the assembly made or not a turn, either to the left or to the right. The angular movement can be obtained in any known manner, for exa by mounting the bolt arm pieces 307 secured to the fixed part 301. Suitable elastic means, such as for exa a spring 310, can extend between the respective free ends of the parts of arm 305 and 306, the resilient means 310 providing a force that moves the parts 305 and 306 to return them to the position shown with full lines in Figure 14. Means are provided to limit the degree of angular movement that the arm pieces 305 and 306 describe with respect to the fixed part 301. Preferably, such means take the form of bolts 308 and 309 secured in the fixed part 301 and intended to make contact with the surface of one or the other of the arm pieces 305 and 306. When it occupies the position shown with full lines in Figure 14, which corresponds to the forward running position in a straight line, no force is applied to the roller 304. since the stop bolts 308 and 309 act to prevent the arm pieces 305 and 306 from contacting said roller 304. As the link piece 302 moves either to the left or to the right, the roller 304 makes contact with one or other of the arm pieces 305 and 306 in order to move it in the downward direction, as indicated by the arrows, overcoming the pressure applied by the spring 310. until the edge of the arm piece reaches it rests against the roller 304 is in substantially parallel relationship with the fixed part 301. When the parts are in such a position no pressure is applied on the roller 304. Therefore, the user will feel a resistance towards one or the other side of the center , until the corresponding one of the arm pieces 305 and 306 moves down towards the fixed part 301 to the maximum possible degree, at which point there is no resistance in the handling to effect a change of direction. ion Such an arrangement tends to maintain the direction in the central position but has little or no effect on any other steering position. The shape of the free end of the parts 305 and 306 can be varied to modify the "tactile sensation" that occurs when driving the assembly. In an unillustrated embodiment, the free end of one or the other of the arm pieces 305 and 306 or both could be curved in the upward direction, to give rise to an increase in tension the more the means of handling the carriage are moved from the forward position in a straight line. However, in the illustrated embodiment, the free end of each of the arm pieces 305 and 306 has a shape such that the spring tension is bypassed when the assembly total is made to go in a direction other than the of walking in a straight line forward. The embodiment of Figure 14 acts to counteract any tendency of the steerable wheels of the assembly to "drift" away from the position corresponding to the forward and straight line travel. In contrast to the embodiment of Fig. 13, the embodiment of Fig. 14 acts only within a predetermined order of displacements of the link piece 302, and the attached piece 303. It should be understood that the newly described and defined invention extends to encompass all alternative combinations of two or more of the individual particulars mentioned or apparent from the text in the drawings. All of these different combinations constitute various alternative aspects of the invention. It should be understood that the term "understand" or its grammatical variants is used equivalent to the term "inciuir" and should not be interpreted as excluding the presence of other elements or particularities.

Claims (25)

1. A load carrying assembly that can be moved by hand that includes a chassis that has a plurality of wheels arranged as a first series of wheels and a second series of wheels, each wheel rotates and pivots relative to the chassis; the wheels of the first series of wheels being connected by a first articulation, and the wheels of the second series of wheels being connected by a second articulation; one of the wheels of the second series of wheels being attached to the opposite wheel of the first series of wheels by a connection such that when one of the wheels of the first series of wheels is pivoted in a direction relative to the chassis, all wheels of the first series of wheels oscillate in that direction to unison, and all the wheels of the second series of wheels oscillate in unison in the opposite direction; and wherein each wheel has basically a vertical oscillating stationary axis which may oscillate relative to the chassis; a hub being mounted on each stationary oscillating axis, each wheel being rotatably mounted on a stub axle, each stub axle being mounted on its respective hub away from the stationary oscillating shaft to allow each wheel to act in an angular manner .

2. The assembly as claimed in claim 1, wherein there are two wheels in the first series of wheels located on either side of the chassis and there are two wheels in the second series of wheels on either side of the chassis.

3. The assembly as claimed in claim 1 or claim 2, wherein the oscillating stationary axle is attached to the chassis and the chassis commonly has two separate and parallel longitudinal members extending between the first series of wheels and the second series of wheels.

The assembly as claimed in claim 4 [sic], wherein each hub is joined to a connecting member, the first link connected to the joining members of the first series of wheels to the far ends thereof from the oscillating stationary axes.

The assembly as claimed in claim 4, wherein the second joint connects the joining members of the second series of wheels to the remote ends thereof from the oscillating stationary axes 6.

The assembly as claimed in the claim 4, wherein the hub of one of the wheels of the second series of wheels has another member extending therefrom; and the hub of the opposite wheel of the first series of wheels has another member extending therefrom; the other members are united by the union.

The assembly as claimed in any of claims 3 to 6, wherein at least one transverse member is provided extending between and secured to the longitudinal members.

8. The assembly as claimed in claim 7, wherein there are two transverse members one associated with the first series of wheels and another associated with the second series of wheels.

9. The assembly as claimed in claim 7, wherein the at least one transverse member is a basket.

10. The assembly as claimed in claim 8, wherein a body connectable to the chassis is provided, the connection to the first end of the chassis being the first articulation.

An assembly carrying movable cargo including a chassis having a first end and a second end, which provide a plurality of wheels accommodated as a first series of wheels a or adjacent to the first end of the chassis and a second series of wheels in or adjacent to the second end of the chassis, each wheel rotates and pivots relative to the chassis; wherein a lever means is provided to act on at least one of the second series of wheels to establish assembly in at least three different modes of operation, all three modes include: straight line travel such that none of the plurality of wheels is steerable (forward or reverse) but all are kept rotating, the fully steerable travel in which all wheel pluralities are steerable (again forward or reverse) and rotatable, and a brake mode to prevent rotation of at least one of the second series of wheels.

12. The assembly as claimed in claim 11, when fitting an assembly as claimed in any of claims 1 to 10.

The assembly as claimed in claim 12, wherein the connector member extends to out from the hub of each wheel of the second series of wheels, to each joining member of the second series of wheels there being connected on a pivot a lever member, the second joint being attached to the lever members at the far ends thereof from the union members.

The assembly as claimed in claim 13, wherein the lever members are pivotable to the joint member to provide the three modes of operation.

15. The assembly as claimed in claim 14, wherein the oscillatory stationary shaft of at least one of the wheels of the second series of wheels is fixedly mounted to a fastening member in a longitudinal projection and outwardly.; at least one of the lever members meshed with the fastener member to provide the straight line travel mode.

The assembly as claimed in claim 15, wherein the clamping member has a groove at the end thereof remote from the stationary oscillating shaft, the groove being adapted to receive therein a portion of the lever member when in the stationary mode. straight line trip.

The assembly as claimed in claim 14, wherein at least one of the wheels of the second series of wheels has a bushing on its stub axle secured to the wheel, the bushing has a plurality of radially directed projections; At least one of the lever members has a stud adapted to engage between the projections on the hub to prevent rotation of the wheel and thus provide the braking mode.

18. The assembly as claimed in claim 17, wherein the joint member has an opening therein to allow the stud to engage between the projections, the aperture having a surface to which the stub is in contact for a portion of the pivoting movement of the lever member between the braking operation mode and the 1-inch straight mode to provide the fully steerable travel operation mode.

19. The assembly as claimed in any of claims 13 to lfi, wherein the second articulated member is operated by foot pressure to move the lever members to and from the three modes of operation.

20. An apparatus for controlling the direction of travel of a steerable assembly, the apparatus includes: (i) a first member associated with a wheel coupling bar operably connected to one or more steerable wheels of assembly (ii) at minus another member associated with a fixed frame member of the assembly, the at least one other member being selectively and continuously pivotable with relative movement to the fixed chassis member between the inoperative and operating end positions; and (iil) a spring means associated with at least one other member, the arrangement being such that, in use, when the steerable wheels of said assembly undergo a change of direction, the first member and the at least one other member are in contact, by means of which the spring means acts to return the at least one other member to its inoperative position, with which it corrects the direction of said mount.

The apparatus as claimed in claim 20, wherein the first member includes a safety rod attached to and generally extending perpendicular from the wheel coupling rod to at least one other member, and the rotating joint turning means. to the rod at the end of it away from the coupling bar of the wheels.

22. The apparatus as claimed in claim 21, wherein at least one other member includes a first other member and a second other member, the second another member being a mirror image of the first other member; the first other member and the second other member being joined by a pivot to the fixed chassis member and having located therein the first member being in the inoperative final position; the spring means extends between the first other member and the second other member.

23. The apparatus as claimed in claim 22, wherein each of the first other member and the second other member has an inner face, the inner faces pointing to each other, being basically a "V" shape with a cut towards outside the inner face, the rotating means meshing outside-out to provide unequal pressure to the rotating means as if moving toward the final operative position.

The apparatus as claimed in claim 22 or claim 23, wherein the first other member and the second other member are separate and generally parallel when in the inoperative final position, the fixed chassis member has a means of space secured thereto. between the first other member and the second other member.

25. The apparatus as claimed in claim 23, in

29. The assembly as claimed in any one of claims 1 to 10, or 12 to 19, when set with the apparatus of any of claims 20 to 28 and wherein the wheel coupling bar is the first joint or the second series of wheels.