GB2261652A

GB2261652A - Lifting and transporting apparatus

Info

Publication number: GB2261652A
Application number: GB9221710A
Authority: GB
Inventors: Daisuke Fujii; Yoichi Oshima; Toshihiro Suzuki
Original assignee: Kobe Steel Ltd; Fujii Corp Co Ltd
Current assignee: Kobe Steel Ltd; Fujii Corp Co Ltd
Priority date: 1991-10-25
Filing date: 1992-10-15
Publication date: 1993-05-26
Anticipated expiration: 2012-10-15
Also published as: GB9221710D0; GB2261652B; KR950005363B1; KR930007745A

Abstract

A lifting and transporting apparatus comprises a load support 8, which is moveable up and down a support frame 1, and a hand truck B which is detachably mounted on the support frame 1 by means of hooks 24 and releasable fastener 7 (and associated engaging member 30). The load support, and a load fitted thereto, is driven up the support frame by means of a gas spring (11 fig. 7 not shown) mounted inside of a hollow vertical pipe 15. A locking means (3 fig. 2 not shown) is provided to lock the load support in its lower position. Retainer portions 10 and ground contact portions 9 are provided at respective upper and lower ends of the support frame 1 to allow the support frame 1 to be leant up against a truck onto which the load is to be lifted, with the aid of the gas spring, once the hand truck B has been removed (see fig 4, not shown). <IMAGE>

Description

The present invention relates to a forklift or carrier for lifting, to a desired level, a heavy load, which could not be easily lifted by a worker, such as a casing and a baggage which is filled with a heavy article or a high pressure gas cylinder and for alternatively unloading the load away from a stack of loads. The forklift is also convenient for delivering the load from a predetermined place to a desired place where the load is lifted to a high level, or alternatively for unloading the load from the high level place and delivering the load to a desired place. The forklift is sometimes used to lift the load to a truck.

Conventionally, when a load such as a gas cylinder and a casing or baggage that is filled with a heavy article, that could not be easily lifted and to which a conventional forklift could not be applied is to be lifted to a desired place such as a loader of a truck, the load is lifted and loaded thereon by a worker. On the other hand, when the load is unloaded from the loader, soft mat-like materials or used tires are laid on the ground and the loads stacked on the loader are pulled and fallen onto the mat-like materials. These works are very hard and need the worker to take a unnatural posture for lifting/unloading the loads. This leads to large fatigue and back-ache. Sometimes, the load is accidentally falled down to injure hands and feet of the worker, which is very dangerous.

The present inventors have developed a wheeled carrier for solving the above-noted problems, and made the present invention through repeated experiments based upon the fact that when a load is loaded/unloaded at a desired place with a wheeled carrier, a body of the carrier must be fixed by a certain method of, for example, applying a brake force to wheels so that the operation is troublesome and when a large amount of load is to be delivered and lifted to a desired place, it is practically better and convenient to first deliver the load to the desired place with the wheeled carrier, and then to pushingly ascend/descend the load with a specialized loading/unloading machine.

According to the present invention, there is provided a load pushingly ascending/descending carrier apparatus comprising: a load pushingly ascending/descending carrier including a load support frame provided movably up and down for lifting a load on an upper surface of a machine frame having a structure which bridges between the ground and a place where the load is lifted; a lock mechanism provided between the machine frame and the load support frame for fixing an up-and-down movement of the load support frame; and a lifting mechanism for moving the load support frame while supporting the load on the load support frame when the lock mechanism is released; and a movable vehicle having a handle at its end portion and wheels at its proximal end portion, wherein the load pushingly ascending/descending carrier is detachably mounted on the movable vehicle and a releasable fixing mechanism is provided between the load pushingly ascending/descending carrier and the movable vehicle.

According to another aspect of the present invention, there is provided the lock mechanism is so constructed that a proximal end portion of a foot operated arm of the lock mechanism for preventing the upper movement of the load support frame is pivoted on a lower portion of one of vertical pipes of the machine frame; the other distal end of the foot operated arm is projected to the outside of the lower portion of the other vertical pipe; and a foot operated pedal is provided at the projected distal end, whereby the foot operated pedal is operated to release the lock mechanism.

According to still another aspect of the invention, there is provided a shielding or protective member through which the opposite side is visible is provided to an opening portion of the machine frame on which the load support frame is movably mounted.

According to the first aspect of the invention, when the load is lifted up, the load a is laid on the load support frame of the load pushingly ascending/descending carrier fixed to the movable vehicle by the fixing mechanism. The carrier is moved to an optimum position by using the vehicle as a delivery means.

The carrier is removed from the vehicle by releasing the fixing mechanism. The carrier is kept to stand on the ground. The carrier is bridged between the ground and the place where the load is lifted, like a ladder. When the lock mechanism is released, the load support frame is moved upwardly while carrying the load by the lifting mechanism. Accordingly, while utilizing the inertia of the upward movement, the load is slidingly lifted up to a place where the load is to be lifted.

Inversely, when the load is lowered from a high level place to a low level place, in the same manner, the carrier is bridged between the high level place and the ground. The lock mechanism is released, the load support frame is moved upwardly by the lifting mechanism. The load is laid on the load support frame which has been moved upwardly. Then, the load support frame is moved downwardly against the pressure of the lifting mechanism under the condition that the load is laid on the load support frame. The load support frame which has been moved downwardly is retained by the machine frame by the lock mechanism. The carrier is kept to stand on the ground. The load is lowered onto the ground from the load support frame or the load is moved to a desired place by the vehicle and is then lowered.

Also, when the load is moved to a predetermined place, the carrier and the vehicle are fixed to each other by the fixing mechanism, and the load is laid on the load support frame. The handle of the vehicle is gripped by the worker's hands to draw or push the vehicle like a handle push vehicle. It is therefore possible to carry the load supported to the load support frame to the desired place. When the fixing mechanism is released, the carrier is removed from the vehicle.

According to the second aspect of the invention, when the foot operated pedal is operated, the lock mechanism is released.

The load support frame is moved upwardly against the weight of the load by the pushing force of the lifting mechanism.

Accordig to the third aspect of the invention, by using the shielding or protective member, it is possible to prevent a part of the body of the worker from being entrained into the opening of the machine frame.

In the accompanying drawings: Fig. 1 is a perspective view showing a state where a load pushingly ascending/descending carrier and a movable vehicle according to a first embodiment of the invention are separated from each other; Fig. 2 is a frontal view showing the apparatus according to the first embodiment; Fig. 3 is a partially fragmentary bottom view showing the mechanism for moving up and down the load support frame relative to the machine frame of the carrier according to the first embodiment of the invention; Fig. 4 is a partially fragmentary, side elevational view showing a state where the carrier according to the first embodiment is used; Fig. 5 is a side elevational sectional view showing the fixing mechanism in a state where the fixing mechanism is released; ; Fig. 6 is a side elevational sectional view showing the engagement mechanism in a state where the engagement mechanism is in operation; Fig. 7 is a partially fragmentary frontal view showing a primary part of a pedal operated mechanism in accordance with a second embodiment of the invention; Fig. 8 is a backside perspective view showing the load carrier according to a third embodiment of the invention; Fig. 9 is an illustration of the working order for unloading a filled gas cylinder away from the loader of the truck and an empty gas cylinder is loaded on the loader, showing a state where the carrier is bridged to rest the loader; Fig. 10 is an illustration of the working order for unloading a filled gas cylinder away from the loader of the truck and an empty gas cylinder is loaded on the loader, showing a state where the filled gas cylinder is descended;; Fig. 11 is an illustration of the working order for unloading a filled gas cylinder away from the loader of the truck and an empty gas cylinder is loaded on the loader, showing a state where the filled gas cylinder has been descended; Fig. 12 is an illustration of the working order for unloading a filled gas cylinder away from the loader of the truck and an empty gas cylinder is loaded on the loader, showing a state where the gas cylinder is delivered; and Fig. 13 is an illustration of the working order for unloading a filled gas cylinder away from the loader of the truck and an empty gas cylinder is loaded on the loader, showing a state where the empty gas cylinder is ascended.

The present invention will now be described with reference to the accompanying drawings in which Figs. 1 through 6 show a first embodiment, Fig. 7 shows a second embodiment and Fig. 8 shows a third embodiment, respectively.

First, explanation will be made to the first preferred embodiment of the invention, in which a load a such as a high pressure gas cylinder and a casing or baggage which is filled with heavy articles and which is difficult for workers to lift up is loaded onto or unloaded from a loader b of a truck by the carrier for loading/unloading the load.

The carrier A for pushingly loading/unloading the load includes a load support frame 2, for pushing and lifting the load a, provided movably up and down to an upper surface of a machine frame 1 having a structure which may bridge between the ground and a place to which the load a is pushingly lifted; a lock mechanism 3 for restricting and fixing the vertical movement of the load support frame 2, which lock mechanism 3 is provided between the machine frame 1 and the load support frame 2; and a lifting mechanism 4 for lifting the load support frame 2 while supporting the load a when the lock mechanism 3 is released. A movable vehicle B includes a handle 5 at its upper end and a pair of wheels 6 at its proximal end. The carrier A is detachably mounted on the movable vehicle B. A releasable fixing mechanism 7 is provided between the carrier A and the vehicle B.

The bridge structure of the carrier A will be described in more detail. A ground contact portions 9 are provided at both right and left lower ends of the machine frame 1 so as to be rotatable about a shaft 9'. Retainer portions 10 are provided at upper ends of the machine frame 1 for retaining the carrier A to a loader b of a truck when the ground contact portions 9 are located at a predetermined position on the ground and the upper portion of the machine frame 1 is bridged or rested obliquely to the loader b of the truck. With the retainer portions, it is possible to stably bridge the carrier A between the loader b and the ground.

As shown in the drawings1 the retainer portions 10 may have means for adjust a fixed angle for the retainer portions 10.

With such a structure, it is possible to bridge the carrier A in a stable manner between the ground and the loaders b which are different in level. Right and left vertical pipes 12 have a hollow cross section. Guide frames 13 which are confronted inwardly with each other inside the vertical pipes 12 and which have a U-shaped cross section and a size smaller than that of the vertical pipes 12 are provided with their openings 13' toward the inside. Right and left vertical support pipes 14 of the load support frame 2 are made of hollow pipes. A vertical support pipe 15 in the middle of the load support frame 2 is made of a hollow pipe having a larger diameter than that of the vertical support frames 14. A plurality of lateral pipes 41 are provided between the vertical support pipe 15 and the vertical support pipes 14.A plurality of rollers 19 are rotatably juxtaposed by utilizing the lateral pipes 41 to thereby constitute the load support frame 2. L-shaped guide pipes 16 are fixed to right and left ends of upper and lower portions of the load support frame 2 so as to project outwardly. Laterally projecting pipes 16' of the guide pipes 16 are engaged with the openings 13' of the guide frames 13. With such a structure, the load support frame 2 may be slidingly moved up and down relative to the machine frame 1 by the guidance of the guide frames 13.

The lifting mechanism 4 will be described in more detail.

In the embodiment shown, a "gas spring" 11 is used which is suitable for an energy source of the lifting mechanism 4.

A load receiving plate 8 is provided perpendicular to a lower portion of the load support frame 2. A cylinder portion of a "gas spring" 11 is inerted into an interior of the hollow vertical support pipe 15. An end of a piston rod 11' of the "gas spring" 11 is pivotally attached to a bracket 18 located in the middle of a lateral beam 17 provided at a lower portion of the machine frame 1. The cylinder head at the other end of the "gas spring" 11 is fixed to an upper portion of the vertical support frame 15.

When the lock mechanism 3 provided between the machine frame 1 and the load support frame 2 is released, the piston rod 11' of the "gas spring" 11 is projected by the gas pressure of the compressed gas sealed within the cylinder of the gas spring 11. Because the piston rod 11' is fixed to the lateral beam 17 of the machine frame 1 and the cylinder head of the "gas spring" 11 is fixed to the vertical support pipe 15 on the load support frame 2 side, the load support frame 2 is moved upwardly toward the upper portion of the machine frame 1 while sliding relative to the machine frame 1 along the guide frames 13 of the machine frame 1 under the condition that the load a is supported thereto. Thus, the worker may readily push and lift the load a to the loader b with his human power by utilizing an upward inertia.In this case, since the conveyor effect of the rollers 19 provided around the lateral pipes 41 of the load support frame 2, it is easy to lift the load a to the loader b.

Inversely, when, under the condition that the lock mechanism 3 is released, the load a is laid on the upper portion of the load support frame 2 which has moved upwardly and the load is supported onto the load receiving plate 8 while sliding downwardly, the load support frame 2 is moved downwardly toward the lower portion of the machine frame 1 by the weight of the load a. In the case where the force is insufficient, when the human power assists the movement of the load, the compressed gas within the "gas spring" 11 is further compressed, and the piston rod 11' is retracted and returned back to the original position where the piston rod 11' is lockable. Accordingly, when the piston rod 11' is locked in this condition, the load support frame 2 is fixed at the lowermost position of the machine frame 1.

Since usually, this operation is for unloading, the weight of the load a on the loader 8 provided on the lower portion of the load support frame 2 is utilized as an actuator, and the load support frame 2 may readily be set to the original position by the push-down operation of the load support frame 2. During this operation, since the gas works as a kind of cushion, the load a is not abruptly dropped but is unloaded in a stable condition.

Also, the pushing speed of the "gas spring" 11 is variable by changing the amount of the gas passage, i.e., by changing a diameter of the gas passage hole provided in the piston within the "gas spring" 11.

In the embodiment shown, the gas spring mechanism is used as an energy source for the lifting mechanism. It is however apparant that, instead of the gas spring mechanism, it is possible to use other various mechanisms such as manual push type hydraulic or pneumatic cylinder, a cylinder with an accumulator, a coiled spring and the like.

Also, in the embodiment shown, the structure is used in the load support frame 2 in which a plurality of rollers 19 arranged in a juxtaposed manner to form a roll conveyor system on both right and left sides. In this case, if the right and left lateral pipes 41 are arranged so that the central portion of the conveyor system is concaved as best shown in Fig. 3, it is possible to support in a stable manner a load a such as a gas cylinder which is likely to be rolled.

The lock mechanism 3 shown will be described in more detail with reference to Fig. 2. A lock pipe 40 is projectingly provided on an upper back surface of a left side vertical support pipe 14 of the load support frame 2. An end engagement hook 21' provided at an upper end of an engagement hook plate 21 of the lock mechanism is engaged with the lock pipe 40 against a return spring 23 to thereby prevent the load support frame 2 from moving upwardly. A lock handle 22 is provided on the engagement hook plate 21. When the lock handle 22 is drawn, the engagement hook plate 21 pivotally mounted on a lateral beam 20 which is laterally provided in the middle of the machine frame 1 is rotated about a shaft attachment portion 20', and the end engagement hook 21' is removed away from the lock pipe 40 to thereby release the lock mechanism 3.

When the load support frame 2 is lowered, the engagement hook plate 21 is returned back to the original position by the return spring 23 but the lock pipe 40 is automatically engaged with the end engagement hook 21' while pushing the engagement hook plate 21.

The fixing mechanism 7 will be described in detail. A pair of U-shaped engagement hooks 24 are provided in the lower back surfaces of the vertical pipes 12 of the machine frame 1. An engagement lateral pipe 27 which is to be engaged with the pair of U-shaped engagement hooks 24 are provided in the lower portion of the body frame 25 of the movable vehicle B. Retaining rings 28 are provided around the engagement lateral pipe 27 for restricting right and left positions of the movable vehicle B relative to the carrier A.An engagement male piece 30 which is projected backwardly from a lower middle portion of an upper lateral beam 29 of the carrier A is provided so as to engage with an engagement receiver 32 of an engagement box member 33 provided in an upper lateral pipe 31 of the body frame 25 of the movable vehicle B when the engagement lateral pipe 27 of the movable body B is engaged with the engagement hooks 24 so that the lower surface of the carrier A is overlapped with the upper surface of the movable vehicle B. The engagement receiver 32 is bifurcated so as to have upper and lower pieces to form a laterally U-shaped structure.A T-shaped engagement rod 37 is elastically engaged with upper and lower engagement throughholes 32' formed in the upper and lower pieces of the engagement receiver 32, when the through-holes 32' are aligned with an engagement hole 30' formed in the central end portion of the engagement male piece 30. A retainer bolt 34 is provided behind the engagement receiver 32. The retainer bolt 34 is retained at a retainer plate 33' disposed in the rear potion of the engagement box member 33 through a spring 35 so that the engagement receiver 32 is slidable back and forth within the engagement box member 33.

An engagement beam 36 having a U-shape in cross section is provided at the upper portion of the engagement box member 33.

Through-holes 36' are formed in the vertical direction in the central portions of the upper and lower plates of the engagement beam 36. The T-shaped retainer rod 37 is inserted vetically into the upper and lower through-holes 36'. An engagement stepped portion 37' is formed on the T-shaped retainer rod 37.

A compression spring 38 is interposed between the engagement stepped portion 37' and the upper plate of the engagement beam 36 to thereby bias the T-shaped retainer rod 37 downwardly.

When the T-shaped retainer rod 37 is lifted upwardly, the engagement receiver 32 is pushed forwardly by the spring force of the spring 35, and the lower end of the T-shaped retainer rod 37 is pressingly supported to the upper surface of the engagement receiver 32 under the condition that the retainer rod 37 is biased downwardly by the spring force of the spring 38.

In brief, in operation, the carrier A is kept to stand up, and the movable vehicle B is also kept to stand on the ground by lifting upwardly the handle 5 about the wheels 6. Then, while engaging the engagement hooks 24 with the engagement rings, the engagement lateral pipe 27 is engaged with the hook portions of the engagement hooks 24, and the back surface of the carrier A is overlapped with the front surface of the movable vehicle B.

The engagement male piece 30 is inserted into the upper and lower pieces of the engagement receiver 32. As a result, the end of the engagement male piece 30 causes the engagement receiver 32 to move backwardly against the spring 35. When the engagement hole 30' is aligned with the retainer through-holes 32', the T-shaped retainer rod 37 which is elastically depressed onto the engagement receiver 32 is inserted into the engagement through-holes 32' and the retainer hole 30' thereby fastening the carrier A and the movable vehicle B in a one-piece manner.

In the case where a -gas cylinder a which is filled with gas is carried, the operation of the forklift according to the present invention will now be explained with reference to Figs.

9 through 13.

The case where gas cylinder a which is filled with gas is carried by a truck and unloaded to the worker is described hereunder. First, the forklift according to the present invention which is received in the truck is picked up to the outside. The carrier A is removed away from the movable vehicle B. As shown in Fig. 9, the carrier A is bridged obliquely from the loader b to the ground. In this case, it is important to fasten firmly the ground contact portion 9 and the engagement portion 10, respectively for the safety aspect.

Next, the worker draws or pushes the gas cylinder a on the loader a to carry it to the carrier A. The lock mechanism 3 is released. The cylinder a is slowly descended along the load support frame 2 of the carrier in which the load receiving plate 8 has been raised while utilizing the guide rollers 26 with the bottom of the gas cylinder a directed downwardly as shown in Fig. 10. Thus, the gas cylinder a is supported to the load support frame 2 with the guard 39.

The gas cylinder a is not abruptly fallen down due to the weight of the gas cylinder a because the gas cylinder a is descended by utilizing as a cushion the pushing force of the pushing mechanism 4. Thus, the load support frame 2 on which the cylinder a is stably supported is descended to the lowermost position, so that the lock mechanism 3 is automatically locked.

The worker gets off the loader b, and stand the carrier A as shown in Fig. 11. As shown in Fig. 12, the movable vehicle B is mounted on the carrier A. The worker carries the forklift to a site where the forklift is kept to stand up and the cylinder a is removed therefrom to be set a predetermined position.

The load support frame 2 of the carrier is fixed with a used or empty gas cylinder a instead of the filled gas cylinder.

The carrier and vehicle are moved to the loader b of the truck as a carrier vehicle while again falling down the vehicle. The vehicle is kept to stand at an optimum position. The movable body B is removed from the carrier, and the carrier A is fallen down and bridged to the loader b. Then, the lock mechanism 3 is released, so that the pushing mechanism 4 is operated and the load support frame 2 is moved upwardly.

At this time, as shown in Fig. 13, the gas cylinder a is manually and abruptly pushed upwardly up to the loader b by the worker's power by utilizing the upward inertia while touching and supporting the cylinder a by the worker's hands.

A second embodiment of the invention in which a pedal operating system is employed will now be described with reference Fig. 7. A support plate 44 is suspended from a lateral beam 20 which is laterally provided in the middle of the machine frame 1. A hook member 45 having a hook portion 45' is pivotally provided to the support plate 44. A proximal end of a foot operated arm 42 is pivotally provided on the lower portion side of the vertical pipes 12 of the machine frame 1. The distal end of the foot operated arm 42 is projected to the left side of the left vertical pipe 12 on the left side of the machine frame 1. A foot operated pedal 43 is provided at the projecting distal end of the arm. A pivot piece 49 is provided in the middle of the foot operated arm 42.A coupling rod 51 whose length is adjustable is connected between the pivot piece 49 and the pivot portion 20' of the hook member 45. A retainer rod 52 for retaining the hook portion 45' of the hook member 45 is provided on the right side of the upper lateral pipe 41 of the load support frame 2. A biasing spring 47 is provided against the foot operation between the foot operated arm 42 and the lateral beam 20 provided in the machine frame 1.

When the foot operated pedal 43 is operated, the foot operated arm 42 is lowered against the spring force of the spring 47, and the hook member 45 is rotated about a pin 46. As a result, the hook portion 45' is released from a retainer rod 52, so that the load support frame 2 is moved upwardly by the lifting mechanism 4. When the foot operated pedal 43 is released, the foot operated arm 42 is returned back to the original position by the spring 47, and also the hook member 45 is returned back to the original position. Under this condition, the load a is laid on the load support frame 2, and the load support frame 2 is lowered against the lifting mechanism 4 by the weight of the load a.As a result, the retainer rod 52 rides over the head portion of the hook portion 45' against the spring force of the spring 47 to thereby automatically engage the hook portion 45' with the retainer rod 52 to keep the condition that the load support frame 2 is prevented from moving upwardly.

A third embodiment shown in Fig. 8 will be explained. A shielding or protective member 50 through which the opposite side is visible is used in this embodiment. The shielding or protective member 50 may be made of a net (which may be made of metal, chemical fiber and other suitable material) or a porous plate (punched metal or expanded metal) or a transparent resin plate which is transparent and may prevent the worker's fingers from passing through the protective member. Thus, any kind of material may be used for the shielding or protective member 50 if with such a material, it is possible to prevent a part of the worker, i.ee, particularly his finger from erroneously being inserted through the member to release the lock mechanism 3 and to clamp the finger by the upward movement of the load support frame 2.In this case, if the opposite side is not observed through the protective member, there are various hindrances against the smooth working.

With such a structure according to the invention, the load lifting/unloading device (carrier) is fixed to the movable vehicle; the load is laid on the load support frame of the carrier; the movable vehicle with the carrier is moved to a suitable position for loading/unloading the load; the fixing mechanism is released and the carrier is removed away from the movable vehicle; the removed carrier is bridged between the ground and the place where the load is to be lifted; the lock mechanism is released and the load support frame with the heavy load is lifted upwardly by the lifting mechanism of the carrier; and the load- is easily lifted up to a desired place, i.e., the loader of the truck by utilizing the inertia of the lifting operation. Thus, the worker is free from the hard work such as carrying the load by his hands and shoulder as in the conventional manner.Inversely, when the heavy load is descended from a high level place to a low level place, it is possible to stably descend the load against the lifting mechanism while riding the load onto the load support frame of the carrier which bridges between the two places. Also, in this case, it is possible to use the apparatus as a transporting carrier. It is therefore possible to readily carry out the transportation of the load. Thus, the invention may provide a carrier which is superior in practical use for loading/unloading the loads.

Also, if a pedal operated mode is applied to the release of the lock mechanism, it is very easy to perform the work in practice.

Also, if the shielding or protective member is provided at the opening portion of the machine frame, it is possible to prevent the worker's hands or fingers from being inserted erroneously, thereby eliminating a fear that the hands or fingers would be clamped when the load support frame is moved upwardly. This is superior in safety aspect.

Claims

1. A load pushingly ascending/descending carrier apparatus comprising: a load pushingly ascending/descending carrier including a load support frame provided movably up and down for lifting a load on an upper surface of a machine frame having a structure which bridges between the ground and a place where the load is lifted; a lock mechanism provided between the machine frame and the load support frame for fixing an up-and-down movement of the load support frame; and a lifting mechanism for moving the load support frame while supporting the load on the load support frame when the lock mechanism is released; and a movable vehicle having a handle at its end portion and wheels at its proximal end portion, wherein the load pushingly ascending/descending carrier is detachably mounted on the movable vehicle and a releasable fixing mechanism is provided between the load pushingly ascending/descending carrier and the movable vehicle.

2. The apparatus according to claim 1, wherein the lock mechanism is so constructed that a proximal end portion of a foot operated arm of the lock mechanism for preventing the upper movement of the load support frame is pivoted on a lower portion of one of vertical pipes of the machine frame; the other distal end of the foot operated arm is projected to the outside of the lower portion of the other vertical pipe; and a foot operated pedal is provided at the projected distal end, whereby the foot operated pedal is operated to release the lock mechanism.

3. The apparatus according to claim 1, wherein a shielding or protective member through which the opposite side is visible is provided to an opening portion of the machine frame on which the load support frame is movably mounted.