GB2340819A

GB2340819A - Low lift truck

Info

Publication number: GB2340819A
Application number: GB9919832A
Authority: GB
Inventors: Yasuyuki Nakadegawa; Katsuo Kita
Original assignee: Ashimori Industry Co Ltd; Nippon Light Metal Co Ltd
Current assignee: Ashimori Industry Co Ltd; Nippon Light Metal Co Ltd
Priority date: 1998-08-26
Filing date: 1999-08-20
Publication date: 2000-03-01
Also published as: GB9919832D0

Abstract

A low lift truck has load arms 2 running in tracks in a vehicle (not shown) which are made of aluminium and on the ends of which cleaning pads 22 made of resin material are provided. The truck is of the type having bogies 12 with rollers 16 which are moved relative to cams 6 to raise or lower the load arms. Preferably openings 2a are provided in the lift arm to receive the rollers 16 when the bogies are lowered. The arrangement lowers the operating force required by minimising friction effects. Preferably, the rollers are of resin material also.

Description

2340819

Specification

LOAD HANDLING TROLLEY Technical Field

The present invention relates to a load handling trolley for use in handling goods or cargoes by hand on a bed of a van-type truck and the like. Background Art

A van-type truck is being desired to be equipped with an auxiliary means for carrying packed goods on a pallet in and out of the truck bed with efficiency by hand operation. The load handling trolley disclosed in Japanese Laid-open Patent Publication No. Hei 8(1996)-67246 is known as such a load handling trolley.

The known load handling trolleys are set in channel type rails embedded in the truck bed of the van-type truck. The known load handling trolleys are movable in the rails, and the platform for the goods to be loaded on has a structure raisable and lowerable with respect to a surface of the truck bed.

The known load handling trolleys are traveled in the rails, with the goods loaded on the platform, and thereby the goods on the truck bed are carried in and out. The travel of the load handling trolleys along the rails is operated by hand.

Description on the carrying the goods in by use of the known load handling trolleys will be given below with reference to FIG. 6. Goods 17 are carried in a truck bed 18 of a vantype truck. For efficient loading of the goods on the truck, channel type rails 3 are embedded in four rows in the truck bed 18 of the van-type truck. Two load handling trolleys 50 are first set in two rails 3 at the right side of the truck bed in the four rails 3, respectively. The goods 17 loaded on a pallet 51 are carried in by use of these two load handling trolleys 50.

First of all, the packed goods 17 on the pallet 51 are loaded on the truck bed 18 by using a fork lift or equivalent, as illustrated. Then, operating levers 52 of the load handling trolleys 50 are shifted down to raise the platform (not shown) from a surface of the truck bed 18. Then, the goods 17 are pushed toward the back of the truck bed 18 by a worker, with the pallet 51 on the platform. Si.nce the load handling trolleys 50 are movable in the rails, the goods 17 move toward the back of the 2 truck bed 18 along the rails 3. Thus, one to three packed goods 17 are carried into a portion of the truck bed at the right side thereof.

Then, the load handling trolleys 50 set in the two rails 3 arranged at the right side of the truck bed are moved to the other two rails 3 arranged at the left side of the truck bed, respectively. Then, one to three additional goods 17 are carried into a portion of the truck bed at the left side thereof in the same manner.

It is then necessary that the goods to be carried in are brought into balance so that the truck can be prevented from being inclined. For achieving the required balance in the carrying of the goods, two required minimum load handling trolleys 50 are alternately moved between the right side of the truck bed and the left side of the truck bed, so that alternate selection is made between the carrying of the goods into the right side of the truck bed and the carrying of the goods into the left side of the truck bed.

However, an engager which is a main component of the load handling trolley 50 is usually made of iron, so that the load handling trolley is totally heavy and disadvantageously involves a hard labor that the loaQ handling trolleys must be changed in position many times. It may be a practical way that the load handling trolleys 50 are provided for both rows of rails at the right side and at the left side, but such a way requires four load handling trolleys 50 in all and thus involves cost increase.

Accordingly, it has come to be an important issue to a worker how to reduce the weight of the load handling trolley, to facilitate the change of position of the load handling trolleys.

Also, it is needless to say that it is desirable that a smallest possible force is just required for the worker to travel the load handling trolleys.

In the light of the problems mentioned above, the present invention has been made. It is the primary object of the invention to provide a load handling trolley which is reduced in total weight so that a worker can change the locations of the load handling trolleys with ease.

It is the secondary object of the invention to provide a load handling trolley via which a force required for the worker to travel the load handling trolley with goods loaded thereon, can be reduced to a smallest possible force. Disclosure of the Invention

A load handling trolley according to the present invention comprises an engager having a platform formed intoa narrow elongate form extending along a channel type rail arranged in a truck bed so that it can be fitted movably in the rail; a plurality of bogies having a plurality of running rollers movable along the rail and a pair of roller plates, arranged at right and left sides of the plurality of running rollers, for supporting the plurality of running rollers rotationally in horizontal positions, and received in the engager so as to be moveable longitudinally with respect to the engager; a link mechanism for connecting one end of the engager and one end of the bogies to drive the bogies to move longitudinally relative to the engager; a cam mechanism for raising or lowering the platform of the engager with respect to the bogies in response to a longitudinal movement of the bogies caused by the link mechanism; and an operating means for operating the link mechanism.

The load handling trolley according to the present invention is placed in the rail of the truck bed in such a manner that when the engager is raised with respect to the bogies, the platform can project from a surface of the truck bed, and the engager is raised with respect to the bogies so that it can be moved in the rail, with the goods on the platform, and thereby the goods on the truck bed are carried.

Particularly, the first load handling trolley according to the present invention is characterized in that the engager is made of aluminum and is provided with a resin member slidable over an inside surface of the rail.

It is noted that the term "(made of) aluminum" used herein does not mean pure aluminum but indicates aluminum alloys generally used for a common structural member. Preferably, aluminum alloys of 7,000 series are used. The material of the resin member is selected from polyethylene, polyacetal, polypropylene and nylon. Among others, high density polyethylene is suitable which is lightweight, excellent in wear resistance, and low in frictional resistance. While the components of the rail are usually made of iron, they may be made of aluminum or stainless steel.

According to the first load handling trolley, since the engager which is a main part of the device is made of aluminum, weight reduction of the load handling trolley can be achieved.

Also, the engager is provided with the resin members so that the sliding resistance between the engager and the rail can be reduced. This can I I I eliminate the disadvantage that with the engager made of aluminum which is not so rigid as iron, the sliding resistance between the engager and the rail embedded in the truck bed increases, so that the force required for traveling.of the engager with the goods loaded on is increased.

Thus, the provision of the resin members to the engager can eliminate the disadvantage that although the engager made of aluminum contributes to weight reduction, the force required for the traveling of the engager with the goods loaded on is increased. Thus, weight reduction and minimization of the force required for the traveling can both be achieved.

As a result of this, with the first load handling trolley according to the present invention, since weight reduction and minimization of the force required for the traveling with the goods loaded can be achieved, the effect can also be produced of taking the load off the worker who changes the locations of the load handling trolleys and carries the goods with the load handling trolleys. Accordingly, even a worker of low bodily force can easily carry the goods in or out of the truck bed and the like. The load handling trolley of the present invention is particularly effective for the case of there being a need to alternately change the locations of the right and left load handling trolleys in order to evenly carry the goods into the right and left sides of the truck bed.

Further, the second load handling trolley according to the present invention is characterized in that the resin member is provided at each lengthwise end of the engager in such a manner as to sweep a bottom of the rail and lower parts of the rail at each side when the platform of the engager is lowered with respect to the bogies and is run in the rail, in addition to the characteristic features of the first load handling trolley.

With this construction, the resin member serves a wiping function for the rail. Thus, at the same time as the carrying of the goods by use of the load handling trolley, foreign matters can be removed from the rail. In addition, smooth rotation of the rollers of the load handling trolley can be ensured.

As a result of this, the second load handling trolley according to the present invention can produce the effect that the force required for the traveling with the goods loaded on can be prevented from increasing due to the foreign matters, in addition to the effect of the first load handling 8 trolley. This can produce the effect that the worker's load can be prevented from increasing temporarily due to the foreign matters during the carrying.

The third load handling trolley according to the present invention is characterized in that the platform of the engager is provided with notches for receiving therein top surfaces of the running rollers when the platform of the engager is lowered with respect to the bogies.

Further, the fourth load handling trolley according to the present invention is characterized in that the platform of the engager is provided with notches for receiving therein top surfaces of the running rollers when the platform of the engager is lowered with respect to the bogies, in addition to the characteristic features of the first or second load handling trolley.

This enables the running rollers to have a largest possible diameter within the height range of the rail. Because of this, the force required for the traveling with the goods loaded on can be reduced further. In addition, a bearing location space for the roller can be produced.

As a result of this, with the third load handling trolley according to the present invention, the worker's load can be reduced further. In addition, general purpose ball bearings can be used for the rollers, instead of expensive needle bearings. This can produce the effect that manufacturing costs of the load handling trolleys can be reduced. Further, since the general purpose ball bearing is higher in durability than the needle bearing, improved durability of the load handling trolley can also be achieved.

Also, with the fourth load handling trolley according to the present invention, the abovesaid effects can be produced, in addition to the effects of the first or second load handling trolley.

The fifth load handling trolley according to the present invention is characterized in that at least running surfaces of the ru nning rollers are formed of resin material, in addition to the characteristic features of any one of the first to fourth load handling trolleys.

By virtue of this, the noise originating from the rotating rollers of the load handling trolley running in the rail embedded in the truck bed can be reduced. As a result of this, the fifth load handling trolley according to the present invention can produce the effect that the noise originating from the load handling trolley running in the rail - 1 0 - can be reduced, in addition to the effects of any one of the first to fourth load handling trolleys.

Among others, high-pitched noise originating from an empty load handling trolley running in the rail after the carrying of the goods can be reduced. Brief Description of the Drawings

FIG. 1(a) is a top view of a load handling trolley of an embodiment of the present invention; FIG. 1(b) is a side elevation view of the load handling trolley of the embodiment of the present invention; FIG. 1(c) is a bottom view of the load handling trolley of the embodiment of the present invention; FIG. 2 is an illustration of the operation of the load handling trolley; FIG. 3 is a sectional view taken along line A-A of FIG. 2; FIG. 4 is an illustration of the operation of the load handling trolley; FIG. 5 is a sectional view taken along line B-B of FIG. 4; FIG. 6 is a perspective view showing the state of use of the load handling trolley; FIG. 7(a) is a top view of a load handling trolley of another embodiment of the present - 1 1 - - invention; FIG. 7(b) is a side elevation view of the load handling trolley of the another embodiment of the present invention; FIG. 7(c) is a bottom view of the load handling trolley of the another embodiment of the present invention; FIG. 8 is a table showing test results on the relation between material of an engager and force required for the traveling of the load handling trolley; FIG. 9 is a table showing test results on the relation between types of bearings and durable years of the load handling trolley; and FIG. 10 is a table showing test results on the relation between material of the running rollers and noise.

Best Mode For Carrying out the Invention

The embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a view showing the structure of a load handling trolley of an embodiment of the invention; FIG. 1(a) is a top view thereof; FIG. 1(b) is a side elevation view thereof; and FIG. 1(o) 1 2 is a bottom view thereof. FIG. 2 is a side elevation view of the load handling trolley 1 in the state of a platform 2b being lowered with respect to a bogie 54. FIG. 3 is a sectional view taken along line A-A of FIG. 2. FIG. 4 is a side elevation view of the load handling trolley 1 in the state of the platform 2b being raised with respect to the bogie 54. FIG. 5 is a sectional view taken along line B-B of FIG. 4.

Explanation will be given below, while a lengthwise right side of the engager 2 in FIG. 1 is considered as the front side and a lengthwise left side of the same as the rear side.

The load handling trolley 1 of the present invention comprises an engager 2, a plurality of bogies 54 received in the engager 2, a link mechanism 8 for the bogies 54 to be moved in the engager 2 in a longitudinal direction thereof, a cam mechanism 30 for the platform 2b of the engager 2 to be raised or lowered with respect to the bogies 54 in response to the longitudinal movement of the bogies 54 caused by the link mechanism 8, and an operating means 21 for operating the link mechanism 8.

The engager 2 is formed into a narrow elongate form extending along inner surfaces of the rail 3 so - 1 3 - that it can be fitted movably in the channel type rail 3 (see FIG. 3) arranged in a truck bed 18. The length of the engager 2 may be selectively determined in accordance with the size of the goods 17 to be carried and the number of bogies 54 mentioned later.

The engager 2 has a loading portion la and an operating portion lb. The loading portion la of the engager 2 has a pair of first, right and left, side plates 53 extending narrowly along the inner surfaces of the rail 3, a first top plate 2b extending long along a top surface of the pair of first side plates 53 to connect between the pair of first side plates 53, and a first end plate 58a provided at lengthwise front ends of the pair of first side plates 53 and the first top plate 2b. The first end plate 58a is a lengthwise front end plate, when viewed from the whole engager 2. The first top plate 2b forms a platform 2b for the goods 17 to be loaded on.

The operating portion lb of the engager 2 extends continuously from rear ends of the first side plates 53 of the loading portion la and has a pair of second, right and left, side plates 55 higher than the first side plates 53 of the loading portion la, a second top plate 56 extending long - 1 4 along a top surface of the pair of second side plates 55 to connect between the pair of second side plates 55, and a second end plate 58b provided at lengthwise rear ends of the pair of second side plates 55 and the second top plate 56. The operating portion 1b of the engager 2 extends upwardly beyond the loading portion la from the rail 3 (See FIG. 2). The second end plate 58b is a lengthwise rear end plate, when viewed from the whole engager 2. The second top plate 56 is provided with an aperture 57 for enabling operation of an operating lever 21.

Further, the engager 2 is formed of aluminum, for reduction of its total weight.

In addition, resin members 22 slidable along the inner surface of the channel type rail 3 are arranged at both lengthwise ends of the engager 2, for reduction of sliding resistance of the engager 2 when sliding in the channel type rail 3.

As shown in FIGS. 2 and 3, the resin members 22 have a plate-like form. The resin members 22 are mounted on the engager 2 at both lengthwise ends thereof so that when the platform 2b of the engager 2 is lowered with respect to the bogies 54 and then is run in the rail 3, the resin members 22 can sweep a bottom 3a of the rail 3 and lower parts of the - 1 5 - side walls 3b of the rail 3 at one time. Thus, the three surfaces of the rail 3 can be swept at one time by a single resin member 22 without separating the resin member into the one for bottom use and the one for side wall use.

The resin members 22 have a width slightly larger than the engager 2 and slightly extending laterally from both sides of the engager 2 so that the resin members 22 can abut against the side walls 3b of the rail 3 before the engager 2 abuts thereagainst. The resin members 22 are so disposed that their bottom surfaces can be close to an inner surface at the bottom of the rail 3 when the platform 2b is in its lowered position with respect to the bogie 54. Thus, the resin members 22 are so configured that they can remove foreign matters from the interior of the rail 3 when the platform 2b is traveled in its lowered position with respect to the bogie 54.

It is noted that the resin members 22 may be in the form of a thin plate so as to be adhesive bonded to both sides of the engager 2. Such a variant may not have the function of scraping off the foreign matters and gathering them, but has an adequate function of reducing the sliding resistance between the engager 2 and the rail 3.

- 1 6 - i The platform 2b of the engager 2 is provided with openings 2a for receiving therein top surfaces of the running rollers 16 when the platform 2b is lowered with respect to the bogies 54, as mentioned later.

The engager 2 is fitted in the channel type rail 3 as shown in FIG. 3 and 5 and is placed in the rail 3 of the truck bed 18 in such a manner that when the platform 2b of the engager 2 is raised with respect to the bogies 54, the platform 2b can project from a surface of the truck bed 18, as shown in FIG. 5, while on the other hand, when the platform 2b of the engager 2 is lowered with respect to the bogies 54, the platform 2b can be in a level lower than the surface of the truck bed 18, as shown in FIG. 3.

The openings 2a, provided in the platform 2b of the engager 2, for receiving therein the top surfaces of the running rollers 16, can provide the result that the running rollers 16 having a largest possible diameter within the height limit for the rail 3 can be used, regardless of thickness of the top plate forming the platform 2b. In the case of the load handling trolley shown in FIG. 3, the running rollers 16 having a largest possible diameter within the range corresponding to the - 1 7 thickness of the member forming the platform 2b of the engager 2 can be used. The engager 2 is on upper ends of the roller plates 11.

The increase of the diameter of the running roller 16 can produce the advantage that general purpose ball bearings can be used. When the general purpose ball bearings are used, a unit price of the running roller can be reduced considerably, as compared with the use of needle bearings. As a result of this, the load handling trolley 1 of the embodiment of the present invention can be made available to users at a low price. Also, since the general purpose ball bearings are higher in durability than the needle bearings, the durability of the load handling trolley 1 is also improved.

As shown in FIG. 1, each bogie 54 has two running rollers 16 for the bogie 54 to run along the rail 3; and a pair of roller plates 11, arranged at the right and left sides of the two running rollers 16, for rotationally supporting the two running rollers 16 in a horizontal position.

The pair of roller plates 11 are maintained with a given interval via caulking shafts 13. The two running rollers 16 are rotationally supported by roller shafts 14 between the pair of roller plates 11.

1 8 Surfaces of the running rollers 16 are formed of resin material.

While the load handling trolley 1 of the present invention usually has three bogies 54, FIG. 1 merely illustrates one entire bogie 54 and a part of another bogie 54. The number of bogies 54 to be connected may be properly selected in accordance with the size of the goods 17 to be carried, the size of the engager 2 and the like.

The three bogies 54 are connected to the engager 2 by connecting the respective roller plates 11 to connecting plates 12 and are housed in the engager 2 so that they can move longitudinally relative to the engager 2.

Also, there are provided fall preventing means 60 for preventing the bogies 54 from falling from the engager 2, while enabling the movement of the bogies 54 relative to the engager 2. The load handling trolleys are required to be frequently transferred between the two or more rails 3, as aforementioned. The provision of the fall preventing means 60 is for preventing the bogies 54 from falling from the engager 2 when the trolley is transferred from rail 3 to rail 3.

Each of the fall preventing means 60 includes a connecting link 60a and a pin 60b and is integrally - 1 9 - mounted on a cam mechanism 30 as mentioned later. The cam mechanism 30 includes a slant cam 6 and a cam roller 15, as described later.

The connecting link 60a is rotationally mounted on one side surface of the slant cam 6 fixed to the engager 2 by means of the pin 60b at one end thereof. The connecting link 60a is rotationally mounted on a shaft 15a, provided in the bogie 54, for supporting the cam roller 15, at the other end thereof. Further, vertical and longitudinal space is provided for a mounting portion of the connecting link 60a so that no influence can be exerted upon the relative movement between the engager 2 and the bogie 54 in their longitudinaland vertical directions in the load handling work. The fall preventing means 60 are provided at both sides of the cam mechanism 30.

The fall preventing means 60 is not limited to the one shown in FIG. 1 but is susceptible of such a modification as shown in FIG. 7. In FIG. 7, the fall preventing means 61 includes a bracket 61a and a pin 61b and is provided at a connecting portion of the bogie 54.

The bracket 61a is fixedly mounted to a bottom surface of the top plate 2b of the engager 2 at a position corresponding to the connecting portion of - 2 0 - i the bogie 54. The pin 61b is inserted in a space 61c defined by the bracket 61a and the top plate 2b and extends over between the pair of right and left side plates 12. The pin 61b is shifted in position in the space 61o in response to the relative movement between the engager 2 and the bogies 54 in the longitudinal and vertical directions in the load handling work. Because of this, the bracket 61a is so configured as to have the space 61c by which no influence is exerted upon the relative movement between the engager 2 and the bogie 54.

The link mechanism 8 is housed in the operating portion 1b of the engager 2, as shown in FIG. 1. The link mechanism 8 includes a first link 5 having a generally right triangle surface and a pair of second links 9 having a plate-like form.

The first link 5 is of a generally trigonal prism form and has inside and outside surfaces of a generally right triangle. A hole 5a is bored in a top surface of the first link 5 taken when a vertex of the right triangle at the right angle side is positioned at a corner 59 formed by a second end plate 58b of the operating portion 1b and the top plate 56. The hole 5a, which is for the operating lever 21 to be inserted in, is bored vertically downward from the top surface so that when the - 2 1 - vertex at the right angle side is positioned at the corner 59, the operating lever 21 can be brought into its inverted position.

A first vertex 5b of the first link 5 at an acute angle side thereof is rotationally supported to the operating portion 1b of the engager 2 via a shaft 7. The shaft 7 extends between the pair of second side plates 55 at the top center thereof. A second vertex 5c of the first link 5 at the acute angle side thereof is connected to the pair of second links 9 at one end thereof in a sandwich relation therebetween via a pin 9a.

The other ends of the pair of second links 9 are connected to the pair of roller plates 11 of the bogie 54 at one end thereof via a pin qb.

Thus, the operating portion 1b at one end side of the engager 2 and the bogie 54 at one end side thereof are connected via the link mechanism 8. Therefore, the bogie 54 can be allowed to move longitudinally in the engager 2 by changing an angle 0 formed by intersection of the first link 5 and the second links 9 of the link mechanism 8. The angle 0 at the intersection is obtained by measuring an angle at which the line connecting a center point of the pin 9a and a center point of the pin 9b and the line connecting a center point of the shaft 7 and 2 2 acenter point of the pin ga intersect each other.

The angleo at the intersection of the first link 5 and the second links 9 varies by the pivoting of the first link 5 about the shaft 7. The first link 5 is pivotable downward about the shaft 7 from a position (hereinafter it is referred to as the initial position) at which the vertex of the right-trianglelike first link 5 at the right angle side is in registry with the corner 59 formed by the second end plate 58b and the second top plate 56 of the operating portion lb. When the first link 5 pivots 45 ' from the initial position until it reaches a position (hereinafter it is referred to as the end position) at which the first vertex 5b and the second vertex 5c of first link 5 at the acute angle side are vertically aligned with each other, the pivot of the first link 5 is stopped by stoppers]d.

The stoppers ld are provided in inner surfaces of the pair of second side plates 55 of the operating portion lb, to prevent the first link 5 from pivoting downward more than 45 degree to enlarge the angle 0 at the intersection of the first link 5 and the second links 9 substantially more than 90 degree.

As the first link 5 pivots downward about the - 2 3 - shaft 7 from the initial position, the angleo at the intersection increases, so that the bogies 54 are moved toward the front with respect to the longitudinal direction. Then, when the first link 5 reaches the end position, the pivot of the first link 5 is stopped by the stoppers ld, so that the movement of the bogies 54 in the longitudinal direction is stopped.

Various types of link mechanisms 8 may be adopted without limiting to the illustrated one, as long as they can convert a swinging motion of the operating means 21 to a longitudinal movement of the bogies 54, as mentioned later.

The cam mechanism 30 is a mechanism for raising or lowering the platform 2b of the engager 2 with respect to the bogies 54 in response to the longitudinal movement of the bogies 54 effected by the link mechanism 8. At least one cam mechanism 30 is provided for each bogie. The number of

cam mechanisms 30 may be suitably selected in accordance with the length of the each bogie 54. In FIG. 1, a single cam mechanism 30 is provided for each bogie 54.

The single cam mechanism 30 is located between the two running rollers 16 of the bogie 54. The cam mechanism 30 includes the slant cam 6 fixed on the 2 4 -1 bottom surface of the top plate 2b of the engager 2 and the cam roller 15 rotationally supported by the shaft 15a between the pair of right and left roller plates 11 of the bogie 54.

The slant cam 6 has a slant surface 6c which increases in height as it goes away from the operating portion 1b and a hollow 6a which is provided in continuation to the slant surface 6c elongated to a given level. A portion of the slant cam 6 at the hollow 6a has an enough height to ensure a desired rising of the platform 2b when the cam roller 15 is fitted in the hollow 6a. The highest portion of the slant surface 6c has a height slightly higher than the height to ensure the desired rising of the platform 2b, for providing room to form the hollow 6a.

The cam roller 15 is located at a position at which it abuts with a lowest part of the slant surface 6c when the first link 5 is in the initial position, while it comes to run onto the slant cam 6 as the bogie 54 is moved in the engager 2 toward the front in a longitudinal direction via the link mechanism 8.

The interval between the lowest part of the slant surface 6c and the hollow 6a is adjusted so that when the first link 5 turns from the initial - 2 5 position to the end position, the cam roller 15 moves from the lowest part of the slant surface 6c to the hollow 6a to fit into the hollow 6a. The first link 5 is restraint from turning further from the end position by the stopper ld, so that after fitting in the hollow 6a, the cam roller 15 is prevented moving further to run over the slant cam 6.

As the bogies 54 moves in the engager 2 toward the front in the longitudinal direction via the link mechanism 8, the cam mechanism 30 thus structured drives the cam roller 15 to run on the slant surface 6c of the slant cam 6 to raise the engager 2. When the platform 2b of the engager 2 is raised to a desired level, the cam roller 15 comes to fit in the hollow 6a to keep the platform 2b in the desired level.

The cam mechanism 30 is not limited to the combination of the slant cam 6 and the cam roller 15 but is susceptible of various combinations of others, as long as they can convert the longitudinal movements of the bogies 54 to the upand-down movements of the engager 2. For example, two slant cams 6, which are fixed to the top plate 2b of the engager and the roller plates 11 of the bogies 54, respectively, may be combined together 2 6 in such a manner as to be slidable and able to run onto each other.

The operating means 21 for operating the link mechanism 8 is formed by an operating lever 21 freely insertable into the hole 5a of the first link 5. When the operating lever 21 is inserted in the hole 5a of the first link 5 in the state of the first link 5 being in the initial position, the operating lever 21 takes an inverted upright position.

When the operating lever 21 is shifted 45 toward the rear of the engager 2 from the inverted upright position, the first link 5 pivots about the shaft 7 to the end position. Then, the second links 9 are pushed out toward the front in the longitudinal direction of the engager 2. Then, the bogies 54 are moved in the engager 2 toward the front in the longitudinal direction.

The load handling trolley 1 thus structured of the illustrated embodiment is disposed in the channel type rail 3 provided in the truck bed 18 of the vantype truck (See FIGS. 3 and 5). The channel type rail 3 has a depth which is so adjusted that when the platform 2b is raised with respect to the bogie 54, the platform 2b can project from the surface of the truck bed 18 (See FIG. 5).

- 2 7 - Therefore, when the platform 2b is lowered with respect to the bogie 54, the platform 2b comes to be in a lower level than the surface of the truck bed 18 (See FIG. 3).

Next, the motion of the load handling trolley 1 thus structured of the illustrated embodiment will be described with reference to the accompanying drawings.

As shown in FIG. 6, the load handling trolley 1 is set near the entrance of the truck bed 18. In illustration, two load handling trolleys 1 are arranged in two adjoining channel type rails 3 in the truck bed 18 of the van-type truck, respectively. Then, the operating lever 21 is in the inverted upright position; the first link 5 of the link mechanism 8 is in the initial position; and the platform 2b of the engager 2 is in a lower level than the surface of the truck bed 18, as shown in FIG. 2.

Then, the goods 17 loaded on the pallet 17a are put on the truck bed 18 together with the pallet 17a by a worker using a folk lift and the like. This state is clearly shown in FIG. 3. The platform 2b of the engager 2 is in a lower level than the surface of the truck bed 18 on which the goods 17 and the pallet 17a are loaded. In this 2 8 state, the top surfaces of the running roller 16 are hidden in the openings 2a of the engager 2. This clearly shows that the running rollers 16 having a largest possible diameter which is determined by a depth of the running rail 3 are placed in the openings 2a.

Then, when the operating lever 21 is shifted 45 rearward, as shown in FIG. 4, the first link 5 pivots about the shaft 7 as far as the end position. This causes the second links 9 to be pushed out which in turn causes the bogies 54 to move forward. When the bogies 54 are moved forward, the cam roller 15 provided in the roller plates 11 runs onto the slant surface 6o of the slant cam 6 fixedly mounted to the engager 2 and comes to a stop by fittingly engagement in the hollow 6a of the slant cam 6. As a result of this, the engager 2 is raised with respect to the bogie 54, so that the platform 2b of the engager 2 is put under load of the goods 17 and the pallet 17a, as shown in FIG. 5. Then, when the goods 17 are pushed at an end thereof in FIG. 4, the whole goods 17 on the load handling trolley 1 are easily carried toward the front end of the truck bed 18 via the running rollers 16 rotating in the rail 3.

During the carriage, the load handling trolley - 2 9 - 1 is brought into contact with the inside surfaces of the rail 3 through the resin members 22 projecting toward both side surfaces of the rail 3, rather than through the engager 2, as viewed in FIG. 5. Therefore, the sliding resistance has a dependence on the resin members 22, rather than non-rigid aluminum material from which the engager 2 is formed. Since the sliding resistance of the resin members 22 is smaller than that of the nonrigid aluminum material, one's labor is reduced.

In FIG. 4, when the operating lever 21 is reshifted to the inverted upright position at the front end of the truck bed 18, the first link 5 of the link mechanism 8 is returned to the initial position. The cam roller 15 disengages from the hollow 6a in the slant cam 6 and descends the slant surface 6c. As a result of this, the top ends of the roller plates 11 are put in contact with the bottom surfaces of the top plate 2b of the engager 2, as shown in FIGS. 2 and 3. In this state, the platform 2b of the engager 2 is in a lower level than the floor face of the truck bed 18, so that only the load handling trolley 1 can be carried to the entrance of the truck bed 18 along the rail 3, leaving the goods 17. While the load handling trolley 1 runs in the rail 3 with no cargo at that - 3 0 - time, noise originating from the running is reduced, because the running surfaces of the running rollers 16 are formed of resin material. Also, the resin member 22 whose lower end is close to the bottom surface of the rail 3 serves to scrape off foreign matters in the rail 3 and gather them during the running of the load handling trolley 1.

By repetition of these operations, a plurality of goods 17 are carried in either of the right and left rows in the truck bed 18, as shown in FIG. 6.

For carrying the goods 17 in the other of the right and left rows in the truck bed 18, it is necessary to transfer the load handling trolley I to the other of the right and left rows. The engager 2 of the load handling trolley I is made of aluminum and thus is reduced in total weight. Thus, the transferring work can be facilitated.

Next, description on force and noise will be given, in comparison between the load handling trolleys of the illustrated embodiments and the known load handling trolleys. The load handling trolleys of the illustrated embodiments each have the engager made of aluminum and the remainder made of iron material and are 7.5kg for each. On the other hand, the known load handling trolleys are all made of iron material and are 12kg for each.

3 1 - Thus, the engager can be reduced in weight by about 4.5kg by replacing iron material by aluminum, so the load on a worker can be reduced considerably.

Further, tests were conducted on the force required for the worker to travel the load handling trolley, with the goods loaded on. Differences originating from the presence or absence of the resin member were studied. The tests were conducted by using two load handling trolleys placed in iron rails arranged in two rows, respectively. The running rollers are made of iron. The force required to carry the pallet putting thereon the goods of 1,000kg by use of the load handling trolley at a speed of 5m/ min. were measured. The results are shown in FIG. 8 as TABLE 1.

In TABLE 1, Comparative Examples 1 and 2 show the difference in force required for the carriage originating from the difference in material of the engager. When contact occurs between the side surfaces of the engager and the inside surfaces of the rail, without any resin member, since aluminum. is less sliding than iron, Comparative Example 1 using the engager made of aluminum requires a larger force for the carriage than Comparative Example 2 using the engager made of iron.

On the other hand, when the resin member is 3 2 mounted on the engager, as in the case of Example 2, even if the engager is made of aluminum, the force required for the carriage is reduced, as compared with Comparative Example 2 using the engager made of iron. Thus, when the engager made of aluminum is used, it is absolutely necessary to mount the resin member to the engager.

Further, as shown in Example 1, when the running roller is increased in diameter, as compared with Comparative Example 2, the force required for carriage is further reduced. As a result of this, load on a worker can be further reduced. Thus, it is apparent that it is beneficial that the openings for receiving the top surfaces of the running rollers at the platform of the engager are provided so that the running rollers having a larger diameter can be used.

Further, the increase of the diameter of the running roller can produce the effect that general purpose ball bearings higher in durability than needle bearings can be used, as mentioned above. Then, tests were conduced for comparison of durability originating from the use of the general purpose ball bearings and durability originating from the use of the needle bearings. In the tests, load handling trolleys similar to those of Examples - 3 3 - I and 2 were used. The tests were conducted, using two load handling trolleys set in iron rails arranged in two rows, respectively. The running rollers made of iron were used. A pallet loading thereon cargoes of 1,000kg were moved in reciprocation in a range of 8.8m at a speed of 5m min. by use of the load handling trolleys, to count the number of times until the bearings were broken.

The durable years was calculated from the counted number of times with reference to the standard number of reciprocating motions described below.

Where 1 year = 365 days; the working is done twice per day; and 16 reciprocating motions for each working, the number of times of reciprocating motions reach 11,680 in one year. This figure is defined as the standard number of reciprocating motions in one year. The durableyears was calculated by dividing the number of times of reciprocating motions counted until the bearings were broken by the standard number of reciprocating motions. The results are shown in FIG. 9 as TABLE 2.

It is apparent from TABLE 2 that the durable years of the load handling trolleys using the ball bearings is twice as long as the durable years of the load handling trolley using the needle - 3 4 - bearings. Thus, the use of the general purpose ball bearings higher in durability than the needle bearings contributes to the improved durability of the load handling trolley 1.

Then, noise tests were conducted to study the differences in noise originating from the materials of the running rollers. In the tests, the load handling trolleys used were all the same as that of Example 2, except the material of the running rollers. The tests were conducted, using two load handling trolleys set in iron rails spaced in two rows at an interval of 600 mm, respectively. Noises originated when pallets on which cargoes of carrying loads shown in TABLE 3 were loaded were moved at a speed of 5m/ min. were measured. A noise meter was mounted to an end portion of the pallet at a center of the operating portion of the load handling trolley. The test results are shown in FIG. 10 as TABLE 3.

As shown in TABLE 3, in any of the instances of zero kg carriage, 500kg carriage and 1,000kg carriage, the resin roller produces less noise than the iron roller, for the reason of which troubles originating from noise can be reduced significantly.

Also, as the goods to be loaded decreases in weight, the difference in noise between the both - 3 5 - tends to increase in the range of 3-1ldB. Thus, the noise reduction effect is of significant.

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Claims

What is claimed is:

1. A load handling trolley comprising: an engager having a platform formed into a narrow elongate form extending along a channel type rail arranged in a truck bed so that it can be fitted movably in said rail; a plurality of bogies having a plurality of running rollers movable along said rail and a pair of roller plates, arranged at right and left sides of said plurality of running rollers, for supporting said plurality of running rollers rotationally in horizontal positions, and received in said engager so as to be moveable longitudinally with respect to said engager; a link mechanism for connecting one end of said engager and one end of said bogies to drive said bogies to move longitudinally relative to said engager; a cam mechanism for raising or lowering said platform of said engager with respect to said bogies in response to a longitudinal movement of said bogies caused by said link mechanism; and an operating means for operating said link mechanism, characterized in: that said engager is placed in said rail of - 3 7 - said truck bed in such a manner that when said engager is raised with respect to said bogies, said platform can project from a surface of said truck bed; that said engager is raised with respect to said bogies so that it can be moved in said rail, with said goods on said platform, and thereby said goods on said truck bed are carried; and that said engager is made of aluminum and is provided with a resin member slidable over an inside surface of said rail.

2. A load handling trolley according to Claim 1, wherein said resin member is provided at each lengthwise end of said engager in such a manner as to sweep a bottom of said rail and lower parts of said rail at each side when said platform of said engager is lowered with respect to said bogies and is run in said rail.

3. A load handling trolley comprising: an engager having a platform formed into a narrow elongate form extending along a channel type rail arranged in a truck bed so that it can be fitted movably in said rail; a plurality of bogies having a plurality of running rollers movable along said rail and a pair of roller plates, arranged at right and left sides - 3 8 - of said plurality of running rollers, for supporting said plurality of running rollers rotationally in horizontal positions, and received in said engager so as to be moveable longitudinally with respect to said engager; a link mechanism for connecting one end of said engager and one end of said bogies to drive said bogies to move longitudinally relative to said engager; a cam mechanism for raising or lowering said platform of said engager with respect to said bogies in response to a longitudinal movement of said bogies caused by said link mechanism; and an operating means for operating said link mechanism, characterized in: that said engager is placed in said rail of said truck bed in such a manner that when said engager is raised with respect to said bogies, said platform can project from a surface of said truck bed; that said engager is raised with respect to said bogies so that it can be moved in said rail, with said goods on said platform, and thereby said goods on said truck bed are carried; and that said platform of said engager is provided with openings for receiving therein top surfaces of - 3 9 said running rollers when said platform of said engager is lowered with respect to said bogies.

4. A load handling trolley according to Claim 1 or 2, wherein said platform of said engager is provided with openings for receiving therein top surfaces of said running rollers when said platform of said engager is lowered with respect to said bogies.

5. A load handling trolley according to any one of Claims 1 to 4, wherein at least running surfaces of said running rollers are formed of resin material.

6. A load handling trolley substaUtially as hereinbefore described with reference to the accompanying drawings.

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