AN ARRANGEMENT IN GOODS VEHICLES

Abstract: This invention relates to an arrangement in goods vehicles for handling load-units, such as skips, containers, cisterns and like load-carrying devices. The arrangement comprises a tilt-frame (3) pivotally mounted on the rear part of the vehicle (1) and a carriage (7) which is movable along the tilt-frame and which is intended for coaction with the load units (2). The arrangement includes at least two mutually adjacent hydraulic piston-cylinder assemblies (8, 9) which function to maneuver the carriage (7) and which are mechanically connected together in a manner to enable the carriage (7) to be moved through a distance which corresponds substantially to the combined lengths of stroke of the piston-cylinder assemblies. In accordance with the invention, the piston rods (10, 11) of both assemblies (8, 9) are provided with two hydraulic-fluid passageways (21, 26; 22, 27) which communicate with spaces on mutually different sides of the pistons (24, 25) in respective cylinders.

Description: An arrangement in goods vehicles The present invention relates to a load-handling arrangement incorporated in goods vehicles, such as lorries and trucks for instance and intended for loading and unloading load-units, by which is meant loads in the form of demountable skips, containers, cisterns and the like, said arrangement including a tilt-frame which is pivotally mounted on the rear part of the vehicle, and a carriage unit which is movable along the tilt-frame and which coacts with the load units, said ' carriage being manouvered with the aid of at least two mutually adja¬ cent hydraulic piston-cylinder assemblies which are interlinked mechanically so that the carriage can be moved through a distance corresponding substantially to the combined length of working stroke of the piεton- cylinder-aεsemblies. From the aspect of time and costs, among other things, it has become progressively-'more usual to adapt goods vehicles in a manner which will enable said vehicles to be used for the transportation of so-called demountable load-units such as pre-filled skips, containers, cis¬ terns or the like, normally referred to as load-unit handling, and thereby render it unnecessary to produce a custom-built vehicle for a given form of transportation or for the vehicle to remain stationary over prolonged periods in order to load goods onto or offload goods from the actual platform of the vehicle concerned. To this end, the goods vehicle is normally fitted with a robust frame which can be tilted about a tilting axle at the rear end of the vehicle, with the aid of hydraulic tilting piston-cylinder-assemblies. -When loading or unloading a demountable load-unit onto or from the vehicle, the frame is tilted so as to form a given angle with the ground, whereafter the demountable load-unit iε drawn-up onto or pushed-down from the frame with the aid of a carriage which is movable along said frame and provided with a lifting-and-holding hook device intended for coaction with the demountable load-unit. Movement of the carriage along the tilt-frame is normal¬ ly effected with the aid of a chain-driven mechanism of a kind similar to that used in fork-lift trucks. One of the drawbacks with the use of chains is that chains require continuous maintenance, including lubrication and cleaning, resulting in high maintenance costs. Arrangements which incorporate chains also result in relatively high manufacturing costs and in heavy con- structions. It is of primary interest in the case of goods vehicles to reduce the weight of ancillary equip¬ ment, so as to increase correspondingly the weight of the useful load capable of being carried by the vehicle. ■ The use of a chain-driven carriage also means that the carriage must have connected thereto flexible, hydraulic lines of variable length for manouvering the hydrauli- cally operated devices which are provided for lifting and locking the demountable load-unit onto the tilt- frame and which accompany movement of the carriage. The use of flexible hydraulic hoses always presents a cer¬ tain safety hazard and increases the risk of disturbanc¬ es in operation. With the intention of avoiding the use of chains, endea¬ vours have been made to move the carriage along the tilt-frame with the aid of hydraulic piston-cylinder- assemblies. Problems, however, have arisen as a reεult of the long lengths of working strokes required of such asβemblies, in combination with the forces necessary to carry out such work. The use of telescopic piston- cylinder assemblies has been proposed in this regard. When constructed for the lengths of stroke and forces required in the present context, telescopic cylinders become extremely bulky and heavy, however. The main object of the present invention is to provide a relatively light and simple construction operative to move the carriage along a tilt-frame with the aid of hydraulic piston-cylinder-assemblies. In keeping with the inventive concept, the construction shall also be configured so as to obviate the need for flexible hy¬ draulic lines for transferring hydraulic fluid between the various driven piston-cylinder-assemblies and be- tween said assemblies and auxiliary piston-cylinder- assemblieε mounted on the carriage. To this end, an arrangement of the kind described in the first paragraph of the specification is particularly characterized in that the piston rods of the two piston- cylinder-assemblies are configured with two hydraulic- fluid passageways which communicate with spaceε on different sides of the piston in respective assemblies. This construction enables fluid to be supplied to both the driving piston-cylinder-assemblies and the hydraulic devices mounted on the carriage with the aid of hydrau¬ lic lines of fixed lengths. In accordance with one advantageous embodiment, the two piston-cylinder-assemblies are fixated mechanically in relation to one another and are hydraulically connected in parallel with the aid of hydraulic lines of fixed lengths. In accordance with one preferred embodiment of an ar- rangement constructed in accordance with the invention, one piston rod is connected to the tilt-frame and the other piston rod to the carriage, and both of said piston rods are provided with means for connection to said fluid passageways at their outer ends. An alternative embodiment which provides essentially the same advantages is characterized in that one piston- cylinder-assembly is connected to the tilt-frame, in that the second piston-cylinder-assembly iε connected to the piston rod of the first piston-cylinder-assembly, in that the piston rod of the second piston-cylinder-asεe - bly iε connected to the carriage, and in that the laεt mentioned piεton rod iε provided with meanε for connec- tion to said fluid passageways at its outer end . In thiε embodiment, said one piston-cylinder-asεembly iε provided with fixed connections for pressure fluid and return fluid. The fluid passageways in the piston rod connected to the carriage are preferably connected with hydraulic devices mounted on the carriage, said connection being effected via electrically switchable valve devices. These hydrau- lie devices may include devices for lifting a load unit onto the tilt-frame, and can be subjected to pressure so as to carry-out a lifting movement when the piston rods are urged to their retracted positions in respective cylinders. The lifting deviceε preferably include a gripping hook having a pivotal locking arm which is intended to close the hook in coaction with the load unit to be lifted, thereby providing a reliable, self-locking function. For the purpose of tilting the tilt-frame, it is pre- ferred that the arrangement includes at least one tele¬ scopic piston-cylinder-assembly operative to initiate tilting of said frame, and that the position of the outer end of the piston rod of said telescopic piεton- cylinder-assembly is controlled with the aid of a rod which iε pivotable about the tilting axle of the frame, said end of εaid piεton rod coacting with a εeat on εaid frame. The invention will now be deεcribed in more detail with reference to an exemplifying embodiment thereof illus¬ trated in the accompanying drawings, in which Figure 1 illustrates a lorry carrying a demountable load-unit; Figure 2 illustrates schematically a tilt-frame with associated working carriage mounted on the lorry; Figure 3 is a sectional view of the carriage in the position illustrated in Figure 2; Figure 4 illustrates the mutual connection of the drive piston-cylinder-assemblies of the carriage; Figure 5 illustrates schematically the initiation of a tilting-frame tilting movement; Figure 6 is a sectional view of the carriage in the position shown in Figure 5; and Figure 7 illustrates a continuation of the tilting movement. Figure 1 illustrates a goods vehicle or lorry 1 on which there is mounted a demountable load-unit 2, which may have the form of a skip and which rests on a tilt-frame 3 which can be tilted about a rear pivot axle 4. The reference numeral 5 identifies the vertical leg of a substantially L-shaped lifting-and-locking device which is pivotally mounted on a working carriage which iε movable along the tilt-frame 3. As shown in Figure 2, the tilt-frame 3 includes two longitudinally extending, U-shaped side-beamε 6 in which a slide in the form of a carriage 7 can be moved reci- procatingly in the longitudinal direction of said beams. In the case of the illuεtrated embodiment, movement of the carriage 7 iε effected by means of two mutually adjacent hydraulic piston-cylinder-aεsemblies, the cylinder housings 8 and 9 of which are mechanically connected together. The piston rod 10 of the lower piston-cylinder-aεεembly is attached to the rear end of the tilt-frame, whereas the piston rod 11 of the upper piεton-cylinder-aεsembly is attached to the forward end of the carriage 7. The reference numeral 12 identifieε means for slidingly εupporting and guiding the piεton- cylinder-asεemblies in the side-beamε 6. The carriage-carried arrangement for lifting and locking a demountable load-unit on the tilt-frame includes the aforesaid L-shaped device having a vertical leg 5 and a substantially horizontal leg 13, which is pivotal about a pivot axle 14, see also Figure 3. The L-shaped device can be swung around said axle by means of pivotally connected, hydraulic piston-cylinder-assemblies 15. The reference numeral 16 identifies a hook device compriεing a self-locking actuator arm 17, as described in more detail herebelow. Tilting movement of the frame 3 is initiated with the aid of two telescopic, hydraulic piston-cylinder-assem¬ blies 18 of restricted length of stroke, only one of which assemblies can be seen in the Figure 2 illustra¬ tion. When the maximum length of stroke of these piston- cylinder-assemblies is reached, the tilting function iε taken over by a main tilting piston-cylinder-aεsembly 19 mounted on each side of the frame, as described in more detail herebelow. The reference numeral 20 identifies two pivotal roller-pairs which are intended for coaction with rails on the demountable load-unit to be drawn-up onto the tilt-frame. These pivotal roller-pairs reduce punctiform loading of the load-supporting platform of the vehicle concerned. For the sake of clarity, the carriage 7 is εhown in Figure 2 in a forward position with the pistons of the hydraulic piston-cylinder-assemblies extended to a maximum. When lifting a load-unit onto the tilt-frame 3, the carriage, however, will be located in its other terminal position, with the piston rods of said asse - blieε retracted in their respective cylinder housings, see Figure 4. As illustrated in Figure 4, the piston rods 10 and 11 are provided with two coaxial passageways of which, for instance, the central passageways 21 and 22 also extend through associated pistonε 24 and 25 reεpectively. The surrounding passagewayε 26 and 27 communicate with the space located inwardly of respective pistonε. The piεton rod 10, which according to the aforegoing iε stationary and is connected to the tilt-frame 3, is provided with fixed connections 28 and 29 for connection to the coaxi¬ al passageways 21 and 26 respectively. Movement of the carriage connected to the movable piston rod 11 along the tilt-frame is effected by supplying pressure fluid to the connection 28 while connecting the connection 29 to the reservoir at the same time. Pressure fluid will therewith act between the piston 24 and the cylinder housing 8 and move the housing relative to the piston. The cylinder housing 9 is caused to accompany this movement. Pressure fluid is also supplied through a line 30 to the space located between the piston 25 and the cylinder housing 9, therewith causing the piεton rod 11 to be extended from the cylinder housing 9. The return fluid is fed from the cylinder housing 9, through a line 31 to the cylinder housing 8, and passes out through the connection 29 via the outer passageway 26 in the piston rod 10. The carriage will therewith be moved to the position shown in Figure 2. Return movement of the carriage is effected by switching the connections 28 and 29, εuch as to connect the con¬ nection 29 to the pump and the connection 28 to the reservoir. The pistons will therewith return to the position illustrated in Figure 4 while returning the carriage. The aforesaid function is thus achieved without the use of flexible hydraulic lines. Aε mentioned in the aforegoing, the piston rod 11 is provided with two coaxial paεsageways which enable manouvering of the hydraulically operated lifting-and- locking device mounted on the carriage 7 which is connected to the piεton rod 11. Subεequent to the piεton rod 11 having been urged outwardε to itε extended terminal position with the aid of pressure fluid supplied through the supply line 30, this passageway arrangement enables pressure fluid to be supplied to selected hydraulic devices on the carriage,through the centre passageway 22, a fixed connection 32 and an electrically εwitchable valve mounted on the carriage. Return fluid returns through the connection 33, the outer passageway 27 in the piston rod 11, and the line 31 to the reservoir connection 29 on the piston rod 10. Correspondingly, when the piston rods have been urged into their retracted positions in respective cylinder housingε, the reεtoring preεsure applied to the cylinder housing 9 via the line 31 can be utilized to manouver hy¬ draulic devices on the carriage, said devices being supplied through the connection 33 whereas return fluid is delivered to the connection 32 and the central pas¬ sageway 22 in the piston rod 11 and to the connection 28 on the piston rod 10, via the line 30. Aε will be underεtood, the hydraulic deviceε on the movable carriage can alεo be εupplied with hydraulic working fluid via the stationary connections 28 and 29, without the use of flexible hydraulic lines, which is highly advantageous. As an alternative to the illustrated embodiment in which the cylinder housingε are mutually connected, the cylin¬ der housing 8 can be turned and the rear end of said housing connected stationarily to the tilt-frame, and to mount the upper cylinder housing 9 at the piston rod of the lower piston-cylinder-aεsembly. The piston rod of the upper piston-cylinder-assembly is connected with the carriage, as in the earlier case. This embodiment also avoids the use of flexible hydraulic lines. When using the described arrangement for lifting a load unit, for instance a demountable load-unit onto the goods vehicle, the tilt-frame 3 is tilted-up in the manner illustrated in Figure 5. This tilting movement is initiated by means of the pivotally mounted telescopic piston-cylinder assemblies 18, the outermost piston-rod ends of which coact with respective sea ings 34 on the tilt-frame 3. The telescopic piston-cylinder assemblies 18 ere connected in parallel with the main tilting piston-cylinder assemblies 19, which, subsequent to the telescopic piεton-cylinder aεεemblies having carried out a maximum working stroke, form an angle with the tilt- frame εuch aε to enable said main tilting assemblies to take over the tilting function of the telescopic assemblies. The carriage 7 therewith occupies its rear terminal position, with the piston rodε retracted in reεpective cylinder houεingε, aε shown in the detailed view of Figure 6. As illustrated in Figure 7, the tilt-frame leaves the telescopic piston-cylinder aεεemblieε 18 aε tilting of said frame is continued with the aid of the main tilting piston-cylinder asεemblieε 19. In order to maintain the outermost piston-rod ends of the telescopic piston- cylinder asεemblieε in correct poεitionε in readineεs for the subsequently downwardly tilted frame, a pivotal rod 35 is mounted between a crosspiece which connects said piston-rod ends and the same pivot axle about which the tilt-frame 3 is swung. In preparation for collection of a demountable load- unit, as hereinbefore defined, the lifting-and-locking device 5, 15 " is εwung down to the position illustrated in Figures 5 and 7 by means of the hydraulic piston- cylinder assemblies 15, these asεemblieε being εupplied via the piεton-cylinder assemblieε which drive the carriage 7, aε beforementioned. The open hook 16 can be brought into engagement with a rod or an eye on the load-unit. When the hook is in engagement with the plat- form, the hydraulic piston-cylinder assemblies 15 are placed under presεure, therewith causing the L-shaped device to be swung-up around its pivot axle 14 while simultaneously lifting-up the forward end of the load- unit on the tilt-frame 3. As the forward end of the platform is lifted, said forward end will engage the lever arm 17 and swing said arm towards the leg 5, wherewith the opposite, hook-shaped part 38 of said arm will close the open hook 16. The demountable load-unit thus becomes self-locking by virtue of the described hook mechanism. Subsequent to lifting the forward end of the load-unit onto the rear part of the tilt-frame, the piston-cylin¬ der assemblies which drive the carriage are activated so aε to draw the load-unit up onto the tilt-frame while εwinging down said frame at the same time. When unloading a platform, the aforesaid working steps are carried out in a reverse order. A load-unit can also be off-loaded in a vertical poεition, when the carriage iε located in itε forward terminal poεition, by swinging the tilt-frame to a substantially vertical position. In this working position, the carriage 7 and the hook mechanism can be used as a lifting crane, by moving the carriage 7 vertically along the frame 3. Although the invention has been described with reference to an illustrated exemplifying embodiment thereof, it will be understood that modifications and changes can be made within the scope of the following claims. For instance, the piston-cylinder assemblies operative to drive the carriage 7 can be placed side-by-side instead of on top of one another.

Claims: CLAIMS 1. An arrangement in goods vehicleε for handling load unitε, εuch as skips, containers, cisterns and like load-carrying devices, said arrangement comprising a tilt-frame (3) pivotally mounted on the rear part of the vehicle (1) and a carriage (7) which is movable along the tilt-frame and which iε intended for coaction with the load unitε (2), at leaεt two mutually adjacent hydraulic piεton-cylinder assemblies (8,9) which func¬ tion to manouver said carriage (7) and which are mechan¬ ically connected together in a manner to enable the carriage (7) to be moved through a distance which corre- sponds subεtantially to the combined lengthε of stroke of the piston-cylinder assemblies, c h a r a c t e r i z e d in that the piston rods (10,11) of both assemblies (8,9) are provided with two hydraulic-fluid passageways (21,26; 22,27) which commu- nicate with spaces on mutually different sideε of the pistons (24, 25) in respective cylinders. 2. An arrangement according to Claim 1, c h a r a c ¬ t e r i z e d in that the two cylinders (8,9) are mechanically fixated relative to one another and con¬ nected hydraulically together in parallel by means of hydraulic lines (30, 31) of fixed lengths. 3. An arrangement according to Claim 2, c h a r a c - t e r i z e d in that one piston rod (10) is connected to the tilt-frame (3) and the other piston rod (11) is connected to the carriage (7) , and in that both piston rods (10,11) are provided with meanε (28,29; 32,33) for connection to εaid fluid paεsageways- (21,26; 22,27) at their outer endε. 4. An arrangement according to Claim 1, c h a r a c ¬ t e r i z e d in that one piεton-cylinder assembly iε connected to the tilt-frame; in that the other piεton- cylinder aεεembly iε connected to the piston rod of the first piston-cylinder assembly; in that the piston rod of the εecond piεton-cylinder assembly is connected to the carriage; and in that said last mentioned piεton rod (10) is provided with means for connection to said fluid pasεagewayε at itε outer end. 5. An arrangement according to Claim 3, c h a r a c ¬ t e r i z e d in that the fluid paεεageways (22,27) in the piεton rod connected to the carriage (7) are con¬ nected to carriage-mounted hydraulically-operated devic- es (5,13) via electrically switchable valve deviceε. 6. An arrangement according to Claim 5, c h a r a c ¬ t e r i z e d in that the carriage (7) includes hydrau¬ lically-operated devices (5, 13) for lifting a load unit onto the tilt-frame (3), said hydraulic devices (15) being intended to be placed under pressure for the purpose of performing a lifting movement when the piston rods (10,11) are in their retracted positions in the cylinders of said piston-cylinder assemblies. 7. An arrangement according to Claim 6, c h a r a c ¬ t e r i z e d in that said lifting devices (5, 13) include a gripping hook (16) having a pivotal locking arm (17, 38) which functions to close the hook upon coaction with the load units to be lifted. 8. An arrangement according to any one of Claim 1-7, c h a r a c t e r i z e d in that the arrangement includes at least one telescopic piston-cylinder asεem- bly (18) which iε operated to initiate tilting movement of the tilt-frame (3); and in that the poεition of the outer piston-rod end of the telescopic piston-cylinder assembly is controlled with the aid of a rod (35) which is pivotal about the tilting axle (4) of said frame, said piston-rod end coacting with a seating (34) on the frame (3) .

Inventors: CARLSSON INGEMAR, CARLSSON, INGEMAR
Applicants: INT TRANSPORT SYSTEM DEV AB, INTERNATIONAL TRANSPORT SYSTEM DEVELOPMENT AB
Application year: 1990
Main classification: F15B15
IPC codes: B60P1