GB2039263A

GB2039263A - Improvements in and relating to motor vehicles

Info

Publication number: GB2039263A
Application number: GB7901332A
Authority: GB
Original assignee: NORWICH COACHWORKS Ltd
Current assignee: NORWICH COACHWORKS Ltd
Priority date: 1979-01-13
Filing date: 1979-01-13
Publication date: 1980-08-06
Also published as: GB2039263B

Abstract

This invention concerns aircraft commissary vehicles having a container (18) which can be elevated relative to the chassis of the vehicle (12) by means of a scissors action elevating mechanism having two pairs of struts (28, 30) located on opposite sides of the chassis and a ram (20) acting between the chassis and the underside of the container or between the two pairs of scissors action struts. Elevation of the container (18) causes the feet (42) at the rear end of the struts (28) to move forwardly. A stop (46), Fig. 2, not shown in the form of a peg can be lifted into an elevated position in advance of the rear stops (44) on the chassis so that as the container (18) is lowered the feet (42) engage the stop (46) thereby inhibiting the complete lowering of the container (18). The feet (42) include rollers (70), Fig. 4, not shown, which are held captive on a rail (38) forming part of the chassis member (12). (Fig. 1) <IMAGE>

Description

SPECIFICATION Improvements in and relating to motor vehicles This invention concerns motor vehicles and in particular aircraft commissary vehicles comprising a lorry chassis having a rear container which can be elevated relative to the chassis to allow the container to be aligned with a service entrance on an aircraft fuselage orthe like to allow the contents of the con tainerto be transferred to the aircraft and used and unwanted materials from the aircraft to be transferred to the container.

The mechanism for elevating the rear container on aircraft commissary vehicles normally comprises two scissors pairs of beams mounted the one pair on one side and the other pair on the other side of the vehicle chassis and pivotally joined to the underside of the container at the front end and to the vehicle chassis just to the rear of the cab, the opposite ends of the scissors pairs being slidably received in slots on the underside of the container and slidable along rails towards the rear of the vehicle chassis. One or more hydraulically operated rams are located so as to lift the container relative to the vehicle chassis.

The mechanism for elevating the container has to be serviced and checked periodically and normally this check must be made with the container in an elevated position.

Hitherto the container has been locked in an elevated position by simply inserting a rigid thrust link between two members of one of the scissors pairs when the container is elevated. However such an adhoc arrangement has dangers since the thrust link may slip out or be removed by an unauthorised person whilst the container is being serviced and mishaps may occur due to the service engineer not realising that the container is no longer rigidly held in an elevated position. A sudden release of hydraulic pressure on the ram during servicing could easily result in these circumstances in the container crashing to its lower level and crushing the service engineer in the process.

It is therefore a primary object of the present invention to provide an improved device for locking the container of an aircraft commissary vehicle in its elevated position to admit servicing under safer conditions than has hitherto been the case.

It is another object of the present invention to provide an improved sliding mechanism for causing the lower ends of the scissors pairs to slide relative to the rear of the vehicle chassis.

According to the present invention a stop member is provided adjacent the rear of the chassis of an aircraft commissary vehicle, each said stop member being movable from a lower position which is not engaged buy a sliding foot which moves rearwards as the container of the vehicle is lowered, into an upper position which is engaged by the said sliding foot as it moves rearwards as the container is lowered.

lfthefoliowing procedure is adopted, accidents due to the container dropping during servicing can be largely eliminated.

Prior to servicing, the container is elevated to its maximum height in which the sliding feet of the scissors pairs will be drawn to their foremost position on the slide on the rear of the vehicle chassis.

Thereafter the stop members on opposite sides of the chassis are moved from their lowered position to their upper position and hydraulic pressure in the ram is reduced allowing the container to drop under its own weight. In doing so the sliding feet move rearwards until they engage the two upstanding stop members when further downward movement of the container is inhibited since further rearward movement of the sliding feet is prevented by the stop members.

The hydraulic pressure can be removed altogether and it will be seen that the container will remain at the height determined by the position of the sliding feet along their slideways as determined by the stop members. Unless the stop members themselves shear, it is impossible for the sliding feet to move further rearwards and the container is accordingly locked mechanically at the elevated position determined by the stop members. Servicing of the lifting gear, hydraulic ram, underside of the container etc.

can therefore proceed without any risk of the container accidentally crashing and crushing the operator.

Afterthe servicing procedures have been completed, the stop members can only be moved to their lowered position afterthe ram has been pressurised and the container has been lifted sufficiently to draw the sliding feet in a forward direction to allow the stop members to be moved into their lowered positions. Thereafterthe ram can be operated so as to lower the container until it rests on the chassis.

The stop members preferably constitute shoes which are pivoted to side struts forming the chassis of the vehicle and which are pivotable through 90 from a horizontal position in which the shoe extends forwardly from its pivot into an upright position in which the shoe extends generally vertically relative to the chassis and acts as a stop member to prevent the sliding shoe from moving in a rearward direction beyond the stop.

When the show takes the form of the preferred embodiment, means may be provided for locking the shoe when in its lowered position to prevent rattling and vibration during movement of the vehicle. In general no locking means is needed to hold the shoe in an upright position since in that position the shoe is prevented from moving due to the jamming action of the sliding foot which presses against it under the downward thrust of the weight of the container supported by the two scissors supports on either side of the vehicle.

Lifting is most effectively provided by means of a single double acting ram mounted centrally beneath the container and pivotally joined to the underside of the container at one end and pivotally joined to a transversely extending cross member of the vehicle at the other end. Extending the ram causes the con tainer to be lifted relative to the chassis on the two scissors supports.

Alternatively the ram may be located between two transversely extending cross members adjoining opposite members of the two pairs of arms forming the scissors supports.

Alternatively two rams may be provided situated either between the chassis and the underside of the container or between different ones of the two hinged struts forming the scissors supports on each side of the vehicle.

Where two rams are provided they are preferably connected to a common supply line via a balancing valve so that the pressures exerted by the two rams are equal to prevent differential lifting and distortion or jamming of the elevating mechanism.

According to a preferred feature of the invention, each of the sliding feet previously referred to comprises a stub axle or pivot pin which extends through and is non-rotatable relative to one of the struts forming the scissors support and adjacent one end thereof, and mounted rotatably on the inboard section of the stub axle of pivot pin, a roller having a larger diameter flange at its outboard end, the shoulder defined by the flange engaging the vertical face of a rail having a flat horizontal surface on which the cylindrical surface of the roller is free to run, and the roller is held captive against the rail by means of a bracket through which the stub axle rotatably extends and which includes a section which engages an under surface of the rail parallel to the surface on which the roller runs.

Means is provided for axially locating the strut, roller and bracket on the stub axle and retaining the components thereon. To this end the axle may be formed with enlarged diameter end or one single enlarged diameter end and a ring secured in place by means of a set screw or the like provides the axial location and retention means at the opposite end of the axle.

Where appropriate spacers in the form of washers and the like may be provided between adjoining sections of the assembly and in a preferred embodiment, a cylindrical sleeve is welded into an aperture in one end of the scissors support strut and forms a sleeve bearing through which the stub axle extends.

Preferably the stub axle includes an enlarged diameter head at the outboard end a segment of which is cut away to form a flat surface which abuts against a peg secured to or extending integrally from the out board end surface of the sleeve which is let into the strut so that the axle is prevented from rotating relative to the said strut.

Typically the roller constitutes that part of the sliding shoe assembly which comes into contact with the upstanding stop member when the latter is pivoted into its upright position to constitute an end stop for servicing.

The invention will now be described by way of example with reference to the accompanying drawings.

Fig. 1 is a side view of an aircraft commissary vehicle, Fig. 2 is a side view of the rear of the chassis of the vehicle shown in Fig. 1 shown to an enlarged scale and illustrating the temporary end stop which can be moved into position to secure the container of the vehicle in an elevated position for servicing and the like, Fig. 3 is a plan view of the rear end shown in Fig. 2 when viewed from above and illustrates the end stop in the position shown in Fig. 2, when viewed end on from above, and Fig. 4 is a cross-section on the line AA in Fig. 1 through the rear sliding shoe assembly and supporting rail.

Fig. 1 illustrates an aircraft commissary vehicle comprising a cab 10 mounted on a chassis 12 between front road wheels 14 and rear road wheels 16.

To the rear of the cab is located a container 18 which can be elevated from the position shown to an elevated position by extending ram 20. The latter is pivotally attached to the underside of the container at 22 and at its opposite end to a transversely extending frame member 24 at 26.

Supportforthe container 18 is provided by two scissors supports formed by elongate struts 28 and 30 on the nearside of the vehicle. Similar struts not shown are provided on the opposite side of the vehicle.

The struts 28 and 30 are pivoted at 32 and the forward ends are pivotally secured at 34 in the case of strut 28 and 36 to the chassis 12.

At the rear the strut 28 is formed with a shoe (to be described hereinafter) which slides on a rail denoted by reference numeral 38 and the rearward end of the other strut 30 is slidably received in a slot 40 in the side wall of the container 18.

Similar mountings for the opposite pair of struts on the other side of the vehicle are provided corresponding to 34,36,38 and 40.

The sliding shoe generally designated by reference numeral 42 is prevented from leaving the rear of the rail 38 by means of a fixed end stop 44.

In orderto provide for servicing of the hydraulics and scissors support, an intermediate end stop is provided as shown in Figs. 2 and 3. This comprises a pivotable peg 46 which can be raised from the lowered position shown in dotted outline at 48 into the upright position shown in Fig. 2 by simply lifting the peg up through a slot shown at 50 in Fig. 3 in the upper surface of the rail 38. By appropriately locating the pivot axis 52 along the length of the rail 38, so the precise height at which the container 18 will be retained when the sliding shoe 42 engages the forward edge 54 of the peg 46, can be selected. This height is selected to allow access to the underside of the container with full working headroom above the chassis and typically is such that the underside of the container is approximately 9 feet above ground level.

Although only one peg is shown, it is to be understood that two such pegs are provided, one on one side and the other on the other side of the chassis 12 both located at the same distance from the end stops of which one is shown at 44 so that both scissors supports are maintained in the same angular orientation and both sides of the container 18 are therefore equally supported.

As soon as the sliding shoe 42 (and the corres ponding shoe on the other side) engage against the forward edge 54 and corresponding edge of the two pegs of which one is shown at 46, the downward thrust exerted by the weight of the container 18 is transferred from the ram 20 to the shoes and pegs.

The peg is designed to withstand the maximum thrust to be expected even when the container is fully loaded and is prevented from rotating beyond the upright position shown in Fig. 2 by virtue of the rear edge of the slot 50, denoted by reference numeral 56.

Engagement between the shoes 42 and the pegs 46 therefore allows the hydraulic pressure in the ram to be reduced to zero and for the whole of the hydraulic circuits if necessary to be dismantled or serviced.

Detail of the sliding foot 42 is shown in Fig. 4.

The lower end of strut 28 is shown in Fig. 4 to an enlarged scale. The strut is apertured at 58 at its lower end and a tube 60 is let into the aperture and welded therein. The tube forms a sleeve bearing for the outboard end of a pin or axle 62 the outboard end of which is enlarged at 64. The majority of the enlargement is circular but a segment is removed to form a flat edge 66 which abuts against an abutment 68 welded to the end of the tube 60. In this way the pin 62 is prevented from rotating.

The inboard end of the pin 62 carries a roller 70 the outboard end of which is formed as a circular flange of enlarged diameter 72. A bearing liner 74 contacts the pin 62.

A thrust washer 76 is located between the inboard end of the tube 60 and the end face of the roller 70.

At the inboard end of the roller 70 is a spacer sleeve 78 and sandwiched between the sleeve 78 and a ring 80 which is secured by means of a set screw (not shown) to the pin 62, is situated a bracket 82 which is apertured so as to be a sliding fit on the pin 62 and includes a leg and out-turned foot 84 the purpose of which will be described hereinafter.

The roller rests on and rolls along a rail which is in the form of a right-angled section of mild steel one leg of which is vertical and the other leg of which is horizontal. The section is generally designated by reference numeral 86.

The shoulder formed by the flange 72 and the roller 70 runs against the outboard vertical face of the section 86 and the length of the leg of the bracket 82 is such that the foot 84 extends underneath the horizontal leg of the section 86 as shown. In this way the roller 70 is held captive on the rail 86. The rail 86 corresponds to the rail 38 in Fig. 1.

Claims

1. An aircraft commissary vehicle comprising a chassis having a rear container which can be elevated relative to the chassis to allow the container to be aligned with a service entrance on an aircraft fuselage orthe like, the chassis including a lifting mechanism for raising and lowering the rear con tainerwhich lifting mechanism includes a sliding foot which moves rearwards as the container of the vehicle is lowered, further comprising a stop member adjacent to the rear of the chassis which is moveable from a first position which is not engaged by the sliding foot as it moves rearwards as the container is lowered into an upper position which is engaged by the sliding foot as it moves rearwards, the position of the stop member being such as to limit the downward movement of the containerto prevent the container from dropping to it's lower most position on the chassis.

2. An aircraft commissary vehicle according to claim 1 in which the lifting mechanism includes two sliding feet one on each side of the vehicle chassis and two stop members are provided to engage the two sliding feet.

3. An aircraft commissary vehicle as claimed in claim 1 or 2 in which each stop member constitutes a show which is pivoted to side struts of the chassis, each shoe being pivotable through from a horizontal position in which the shoe extends forwardly from its pivot, into an upright position in which the shoe extends generally vertically relative to the chassis and acts as a stop member for the sliding shoe.

4. An aircraft commissary vehicle as claimed in claim 3 further comprising means for locking the shoe when in its lowered position to prevent rattling and vibration during movement of the vehicle.

5. An aircraft commissary vehicle as claimed in claim 3 in which means is provided for locking the shoe in an upright position.

6. An aircraft commissary vehicle as claimed in any of the preceeding claims wherein the lifting mechanism comprises a single double acting ram mounted beneath the container and pivotally joined to the underside of the container at one end and pivotally joined to a transversely extending cross member of the vehicle chassis at the other end.

7. An aircraft commissary vehicle as claimed in any of claims 1 to 5 in which the lifting mechanism includes a single double acting ram located between two pivotally joined members of the lifting mechanism so that extension of the ram causes a scissors action and an elevation of the container.

8. An aircraft commissary vehicle in which the lifting mechanism includes two rams acting on the lifting mechanism to raise the container as the rams are extended, the two rams being connected to a common supply via a balancing valve so that the pressures exerted by the two rams are equalised to prevent differential lifting and distortion orjamming ofthe lifting mechanism.

9. An aircraft commissary vehicle as claimed in any of the preceeding claims in which each of the sliding feet of the lifting mechanism comprises a stub axle or pivot pin which extends through and is non-rotatable relative to one of the struts forming the lifting mechanism and adjacent at one end of the strut, and mounted rotatable on the inboard section of the stub axle or pivot pin is a roller having a larger diameter flange at its outboard end, the shoulder defined by the flange engaging the vertical face of a rail having a flat horizontal surface on which the cylindrical surface of the roller is free to run, the roller being held captive against the rail by means of a bracket through which the stub axle rotatably extends and which includes a section which engages an under surface of the rail parallel to the surface on which the roller runs.

10. An aircraft commissary vehicle as claimed in claim 9 in which means is provided for axially locating the strut, roller and bracket on the stub axle and retaining the components thereon.

11. An aircraft commissary vehicle as claimed in claim 10 in which the axle is formed with enlarged diameter ends or one single enlarged diameter end with a ring secured in place by means of a set screw at the opposite end of the axle.

12. An aircraft commissary vehicle as claimed in claim 10 or 11 in which a cylindrical sleeve is welded into an aperture in the end of the lifting mechanism strut, the cylindrical sleeve forming a bearing through which the stub axle extends.

13. An aircraft commissary vehicle as claimed in any of claims 10 to 12 in which the stub axle includes an enlarged diameter head at the ourboard end, a segment of which is cut away to form a flat surface which abuts against a peg secured to or extending integrally from the outboard end surface of the sleeve which is let into the lifting mechanism strut so that the axle is prevented from rotating relative to the strut.

14. An aircraft commissary vehicle having a rear container which can be elevated relative to the chassis to allow the container to be aligned with a service entrance on an aircraft fuselage or the like which includes a lifting mechanism and stop beams for engaging the lifting mechanism to restrict the downward travel of the container constructed arranged and adapted to operate substantially as herein described with reference to and as illustrated in the accompanying drawings.