FR2838418A1 - Load-handling trolley has forks moved up and down guide mast by drive including pulley, cable and power cylinder - Google Patents

Abstract

The trolley, comprising a body (10) with ground supporting feet (11, 12) and rollers (13, 14), has forks (20) that are moved up and down a guide mast (30) by a drive with a pulley and cable connected to a power cylinder. The mast has a channel for the power cable and a pair of slideways to guide the forks, and the trolley is controlled by a tiller (15) and a steerable wheel.

Description

<Desc / Clms Page number 1>

 The present invention relates to a load transport carriage.

 A load transport trolley is intended to lift pallets of goods slightly off the ground in order to transport them elsewhere.

 The carriage comprises a frame, carried by a steering and driving wheel controlled by a drawbar, a frame integral with two front longitudinal beams bearing on the ground, the free ends of which are mounted on casters.

 In the area above the two side members extend two branches of a fork intended to carry a pallet to be moved. For this purpose, the carriage is advanced so that the two side members and the two fork legs engage under the pallet, then the fork is slightly vertically translated by an actuator mechanism to lift the pallet from the ground.

 The translation lifting the fork can in particular be carried out by means of a so-called scissor system arranged transversely at the rear of the frame. The scissors are in fact two longitudinal members mutually coupled to the length, in X, by a hinge pin. A jack controls the bringing together of the two lower ends of the two branches of the X and thus causes the rise of the two upper ends, coupled to the fork.

 Such a scissor trolley thus offers a certain range or dynamic height adjustment of the fork, so as to place the pallets no longer on the ground but on supports in height. However, the height adjustment dynamics are limited because the X, in the flat, flat position, must not extend laterally from the frame.

<Desc / Clms Page number 2>

 The present invention aims to propose a solution making it possible to overcome the limitation of the height travel of the fork.

 To this end, the present invention relates to a load transport carriage comprising a frame, provided with stable support means on the ground, and comprising a movable fork for pallet support controlled by drive means in vertical displacement, in operation , characterized in that the fork comprises means for guiding in translation, for example by sliding, on a guide mast, under the action of the drive means.

 Thus, the carriage comprises, in addition to the drive means, guide or sliding means, whereas, in the prior art, the X of the scissors integrated the transmission function of the vertical drive and of holding the fork in the desired relative position when viewed from above.

 According to the present invention, the guide ensures the above maintenance in the desired position in top view, so that it is possible to choose a drive means making it possible to obtain any desired stroke length, by providing a mast of suitable length.

 In an advantageous embodiment, the drive means comprise a flexible link, extending substantially parallel to the mast, for pulling up the sliding means, and for example comprise a pulley for returning the flexible link.

 The flexible link can in particular connect the sliding means to a fixed point on the frame and the axis of the return pulley is mounted at a free upper end of a jack, for adjusting the height of the fork, to

<Desc / Clms Page number 3>

 travel substantially parallel to a direction of mast extension.

 Preferably, the mast has a flexible link passage channel. The mast can also have a longitudinal channel or passage reserved for the jack, which is thus protected and this first to avoid bodily injury.

 The mast can have two twin slides, which allows inexpensive manufacturing.

 The drive means may, in a variant, comprise a jack, extending substantially parallel to the mast, for direct drive of the sliding means.

 The mast can be provided so that it extends substantially vertically along a median longitudinal plane of the carriage.

 A steering wheel control rod can be rotatably mounted on a bearing carried by a lateral offset support relative to the mast. This is particularly interesting in the case of the central mast mentioned above.

 The mast advantageously carries a rotary mounted console.

 The invention will be better understood using the following detailed description of an embodiment of a load transport carriage according to the invention, with reference to the attached drawing, in which: - Figure 1 is a view in perspective left front of the carriage, - Figure 2 is a perspective view of the carriage from the rear right, - Figure 3 shows in more detail, in cross section, a mast associated with the fork, and - Figure 4 is a schematic side view illustrating the operating principle of a mechanical lifting cylinder of the fork.

<Desc / Clms Page number 4>

 The load transport carriage 1 shown in FIG. 1 comprises a frame body or chassis 10 provided with two parallel and lateral front legs or side rails 11, 12 of stable support on the ground. Each spar 11, 12 comprises, in the anterior free end zone, a respective support and displacement roller 13, 14. The body of the frame 10 includes a rear wheel 15 for support and steering, the steering direction of which is controlled by a drawbar 17, articulated in this example. The wheels or casters 13, 14, 15 are arranged along the vertices of a triangle ensuring the desired stability in roll and pitch, that is to say essentially in tilting forwards under the weight of a loaded pallet, carried by two arms or branches 21, 22 of a transport fork 20.

 However here, due to the presence of a central mast 30 (the function of which is explained below) centered along a median plane of the carriage 1, the drawbar 17 and the steering wheel 15 located below are offset laterally, here to the left , substantially in the extension of the beam 11, so that the driver's panoramic field of vision is not limited. The wheels or casters 13, 14, 15 thus form the vertices of substantially a right triangle.

To widen the support polygon thus defined, a stabilizing wheel 16, mounted free in turning rotation, is disposed to the right of the body 10, in a rear position symmetrical to that of the wheel 15 to form a total lift trapezoid substantially of the shape of a rectangle.

 The drawbar 17 is mounted to rotate freely, about a vertical axis, on a bearing 2 of the chassis 10. A horizontal beam or beam 3, of lateral offset of the drawbar 17, comprises, a section, here at the end, provided with elements of

<Desc / Clms Page number 5>

 fixing the foot of the mast 30, such as lights for receiving the mounting bolts of the mast 30, or even studs or receiving lugs, or a welding zone for the mast 30, and the opposite end carries the bearing 2 of the drawbar 17.

 For the sake of clarity of presentation, the wheels 13 to 16 of the carriage 1 are here assumed to rest on horizontal ground, that is to say in the conventional functional position. The explanations of orientation of the constituent elements of the carriage 1 with respect to the vertical or the horizontal are therefore based on this assumption. The generality of the description of the invention should therefore not be considered as limited by this assumption.

 The two branches of the fork 20 extend horizontally forward, above the side members 11, 12 of the ground, and have substantially the same length as these.

 In this example, the fork legs 21 and 22 extend slightly more forward than the support beams 11,12 and each have, in top view, a cutout or elongated opening 23, 24 of size corresponding to the section the spar 11,12 situated vertically from the branch considered 21,22. This complementarity of section shapes makes it possible, as explained below, to lower the fork 20 until practically touching the ground, without the longitudinal members 11, 12 constituting an obstacle to the descent.

 It will be recalled that a pallet for the support of goods comprises an upper plane for placing the goods, consisting of a series of neighboring slats which generally rest on three evenly spaced battens, extending perpendicular to the slats and of sufficient cross section in height so that the side members 11,12 and the branches 21,

<Desc / Clms Page number 6>

 22 can be slid under the slats. The support beams 11, 12 have an occupation in height, with respect to the ground, substantially equal to the thickness of the branches 21, 22.

 As shown in Figures 3 and 4, the fork 20 has a body portion 25 mutually connecting the legs 21, 22. The fork body 25 has a slide 26 which cooperates with the mast 30 of the chassis 10, ensuring sliding guidance of the body 25 and therefore of the fork 20.

 The mast 30 has, in this example, a cross section having a functional part substantially in the form of two opposite Cs, that is to say constitutes a kind of tube comprising a slot with axial extension. For practical reasons, the mast shown 30 is in fact constituted by the assembly of two angles or sections 30A, 30B opposite (fig. 3) with a section in "C cedilla", that is to say substantially in the form of a rectangle, but open on a long side, which has slipped to form an appendage 31A, 31B receiving three legs or spacer plates, like that referenced 60, for connection with its counterpart of the other profile, axially spaced apart according to the height of the mast 30. These are therefore two opposite slides, 30B, twinned, which radially trap the slide 26.

 The slide 26, at the rear end of the fork 20, thus cooperates with the tubular mast 30 and has for this purpose a cross section, that is to say horizontal in operation, complementary to the internal shape of the mast 30 in which here she is housed. The slide 26 has a height dimension sufficient to withstand the torsional torque represented by the weight of the load of the

<Desc / Clms Page number 7>

 pallet, acting at a certain horizontal distance from the mast 30.

 The slide 26 is extended radially by an arm 27 for connection with the two branches of the fork 20, arm 27 projecting through the slot separating the two slides 30A, 30B from the mast 30.

 The driving energy is here provided by an electric motor 41 powered by a battery 40 and controlling a jack 42 for driving back and forth of the fork 20 by sliding on the guide mast 30. All the other members of the carriage 1 occupies a predetermined position in the chassis 10, and only the fork 20 is driven in vertical translation, in the functional position, by the jack 42.

 In this example, the drive connection of the fork 20 by the jack 42 includes a muffle type assembly. Specifically, as shown in Figure 4, the cylinder 42 extends vertically, parallel to the mast 30, adjacent thereto. The lower end of the jack 42 is fixed to the chassis 10, while its mobile upper end carries a horizontal axis 32 of a pulley 31 of return 31 (shown dilated) with a flexible link 33.

 The flexible link 33, such as a cable or as here a chain carried by the pulley 31, connects the slide 26 to a fixed point 19 of the chassis 10 located here at the foot of the mast 30. The fixed point 19 could be elsewhere , but always with an assembly such that the chain 33 is held in the groove of the pulley 31 remains ensured over the entire stroke of the jack 42.

 Thus, in this example, the jack 42 in fact constitutes a support mast of adjustable length, resistant to compression due to the weight of the load, and determining the

<Desc / Clms Page number 8>

 length of the rising strand 34 of the chain 33, connected to the chassis 10, which determines the remaining length for the complementary strand 35, descending from the pulley 31 to the fork 20. The mast 30 has here only one function sliding guide fork 20. It is indeed the cylinder 42 which, by the axis 32, supports the load of the pallet. The mast 30 can however also be used to maintain the jack 42 in the desired upright position, jack 42 which can optionally be housed in the mast 30, in a channel left free by the slide 26.

 As a variant, it will however be noted that it is not compulsory for the axis 32 carried by the jack 42 to have a stroke strictly parallel to the mast 30 and for the pulley 31 to be substantially arranged as here vertical to the mast 30. In Indeed, it suffices that the descending strand 35 is always effectively descending, that is to say that the pulley 31 is always situated at a level higher than that of the fork 20, without necessarily ensuring almost verticality at the descending strand 35. The jack 42 can likewise be tilted vertically, and this is also true for the rising strand 34.

 Still alternatively, other complementary forms, for sliding cooperation between the mast (30) and the slide (26), can be provided. Thus, in an embodiment with kinematic inversion of the previous one, the mast (30), possibly full and for example circular, could cooperate by its external surface with a collar or clamp or a sliding sheath secured to the fork 20.

 The muffle effect, linked to the vertical displacement of the axis 32, results in a vertical displacement of the fork 20 of double the change in length of the jack 42.

Thus, in the retracted position of the jack 42, the fork 20

<Desc / Clms Page number 9>

 occupies its extreme low position at ground level, with a small vertical clearance to the ground to avoid scraping. In the fully deployed position of the cylinder 42, the descending strand 35 is of almost zero length, that is to say that the fork 20 is then almost at the level of the pulley 31. The necessary stroke of the cylinder 42, and therefore the size provided for it, is thus limited, due to the amplification by a factor of 2 of the displacement of the fork 20.

 As a variant, the drive members also comprise a jack, extending substantially parallel to the mast 30, but the jack directly drives the sliding element 26, that is to say is in direct engagement, to push it towards at the top and to bring it back down, or simply authorize its descent under the effect of the weight of the fork 20.

 As a variant, a hoist assembly, that is to say an axis 32 of fixed height, can be envisaged.

 Similarly, the mast 30, here central, could be offset laterally.

 The mast 30 constitutes a kind of bus, in which are housed all the members extending vertically.

 In this example, the free end of the mast 30 carries a substantially flat vertical console 50 rotatably mounted, along a vertical axis, by means of a radial offset bracket. The trajectory of the console 50 is thus tangent to a fictitious cylinder completely containing the mast 30, therefore free of risk of collision with the latter.

 The slide 26 of the mast 30 is in fact here an element guided in translation by means of two opposite pairs 51, 52 and 53.54 of superimposed rollers, only the left pair 51.52 being visible in FIG. 4. The weight of load

<Desc / Clms Page number 10>

 on the fork 20 induces a forward bending torque on the mast 30. The appendix 31A, 31B extends parallel to the median plane of the carriage 1, that is to say that it extends the guide part C-shaped, to increase the mechanical inertia of the mast 30, that is to say increase the torque of resistance to forward bending.

 Thus, the mast 30 is formed from two opposite sections 30A, 30B comprising a C-shaped part, the two opposite end branches of each C of which serve to support the two rollers 51, 52 or 53, 54, to resist the bending torque due to the load. Each end branch therefore comprises a rolling surface of the rollers 51.52 or 53.54, which transmits the bending torque to the mast 30.

Appendix 31A, 31B constitutes a sort of stiffening fabric with extension in a plane substantially parallel to the median plane, and thus opposes bending.

The appendix 31A, 31B is also secured to the plates like 60, for example by welding, on at least one of its two longitudinal surfaces, external or internal.

 Preferably, each profile 30A, 30B is in one piece, that is to say in particular that the appendix 31A, 31B is in one piece with the part in C.

 Appendix 31A, 31B here has the same section all along the mast 30.

 The jack 42 is housed inside the space limited by the two Cs, which thus protect it.

 A spacer 60 halfway up the mast 30 here serves as a fixed attachment point 19 for the flexible link 33.

 The intermediate connecting part 27 is here detachably fixed to the guided part 26, which makes it possible to replace the fork 20 with another tool, such as a spindle or the like.

<Desc / Clms Page number 11>

 The mast 30 here comprises, in the upper part, a rear apron with a horizontal U-shaped section, forming the closing cover of the mast 30. The apron is metallic and can be fixed, by welding or otherwise, to the rest of the mast 30, which increases still the mechanical inertia of the assembly with respect to forward bending.

 The connecting part 27 can be formed of two parallel webs and spaced laterally.

Claims (10)

claims 1. Load transport cart comprising a frame (10), provided with means (11-16) for stable support on the ground, and comprising a movable fork (20) for supporting the pallet controlled by means (31-35, 41,42) for vertical displacement drive, in operation, characterized in that the fork (20) comprises means (25,26) for guiding in translation on a guide mast (30), under the action of drive means (41,42).  2. Trolley according to claim 1, in which the drive means comprise a flexible link (33), extending substantially parallel to the mast (30), for pulling up the guide means in translation (25, 26).  3. Trolley according to claim 2, wherein the drive means comprise a pulley (31) for returning the flexible link (33).  4. Trolley according to claim 3, wherein the flexible link (33) connects the traslation guide means (25,26) to a fixed point (19) of the frame (10) and the axis of the return pulley ( 31) is mounted at a free upper end of a jack (42), for adjusting the height of the fork (20), with travel substantially parallel to a direction of extension of the mast (30).  5. Trolley according to one of claims 2 to 4, wherein the mast (30) has a flexible link passage channel (33).  6. Trolley according to one of claims 2 to 5, wherein the mast (30) comprises two twin slides.  7. Trolley according to claim 1, in which the drive means comprise a jack, extending <Desc / Clms Page number 13>  substantially parallel to the mast (30), direct drive of the sliding means (26).  8. Trolley according to one of claims 1 to 7, in which the mast (30) extends substantially vertically along a median longitudinal plane of the trolley.  9. Trolley according to one of claims 1 to 8, in which a drawbar (17) for controlling a steering wheel (15) is rotatably mounted on a bearing (2) carried by a lateral offset support (3) by relative to the mast (30).  10. Trolley according to one of claims 1 to 9, wherein the mast (30) carries a desk (50) rotatably mounted.