EP0930958A1

EP0930958A1 - Adjustable maintenance creeper

Info

Publication number: EP0930958A1
Application number: EP97916664A
Authority: EP
Inventors: Borge Grimstad
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-10-07
Filing date: 1997-02-21
Publication date: 1999-07-28
Also published as: WO1998015391A1; NO964246L; AU2522897A; NO964246D0

Abstract

Device to provide a correct working position, having a base frame (1) with castors (3) and a lifting frame (2) in between which a scissors-like device (6, 7, 9, 11, 12) and a lifting device (10, 20, 21) are provided. A seat (13) and a swivelling backrest (14) are mounted to the lifting frame (2). The backrest (14) is adjustable at an angle to the lifting frame (2) with the help of a locking and lifting device (15, 16, 17, 18, 19). The base frame (1) can be stabilized to the floor with the help of stabilizers (26).

Description

ADJUSTABLE MAINTENANCE CREEPER

The present invention relates to a rolling device to enable mechanics to achieve a correct working position when effecting repairs under or to the side of vehicles and the like. This type of device is often called a garage creeper or cradle.

Effecting repairs to vehicles and the like is often a strenuous and demanding task for the human body as vehicles are compact and of difficult access. Mechanics are exposed to tiring working positions which cause fatigue and over a certain period of time may result in strain injuries, a consequence of which may be disability and sick leave. This is especially true of repairs which have to be effected under the vehicle or to the sides. In order to access the underside of a vehicle, a mechanic has to lie on his back and, dependent on the space available under the vehicle, must lift or lower the torso and the head in order to gain access to the part in need of attention. To be able to maintain such a working position in which the head has to be lifted from the ground for a certain time, adequate support must be provided for the head in the position required. This is necessary in order to prevent strain on the neck and chest muscles involved in holding the head up and leading to tension and subsequent pain. In addition, the arms will be held in a lifted position over a certain period of time and will often be drained of blood when effecting strenuous work on mechanical parts, this blood drainage resulting in exhaustion.

It is common for vehicles to be placed on service ramps which are lifted from the floor to the desired height, enabling the mechanic to access the underside of the vehicle. The ramp enables the mechanic to stand under the vehicle, but the strain on head and arms remains approximately the same as that described when a creeper is used. In a standing position, the body is more or less vertical but the head must be bent backwards, resulting in considerable strain on the muscles and skeleton of the neck and shoulders.

Nowadays, mechanics effect repairs on vehicles either when lying on their backs under the vehicle or using a so-called creeper. A creeper is a board, equipped with castors, on which a mechanic can lie back before rolling, still lying down, under the vehicle. The creepers at present on the market have a small cushion-like raised part for the head. Such creepers are at a fixed height from the ground and give therefore little opportunity to the mechanic for adjusting his working height relative to the room available under the vehicle. The headrest is likewise fixed on the board and leaves little room for adjustement by the mechanic. There are also on the market a number of frame-like devices equipped with castors, which can be used in combination with a creeper, the creeper being placed on top of the frame in order to obtain a different working height. Such frames used with a creeper, or a creeper alone, do not provide any possibility for adjustment of the height for the head, the lying or sitting position and the height or support for the arms. Thus, they do not present any suitable option for a mechanic who requires acceptable, body-friendly and strain-preventing working positions.

The object of the present invention is to provide a device which can be adapted to each person's working needs in order to achieve an optimal combination of effective work and body-friendly, strain-preventing working positions. In other words, the aim is an ergonomic working position. A device having such an object must satisfy the following requirements:

- it must be possible for the user himself to effect adjustment of all the parts composing the device to provide an optimal working position as the user lies in place on the device

- it must be possible for the device to be displaced on the ground while the user is lying on it

- it must be possible for the device to be stabilized on the floor.

This is obtained with the help of an approximately rectangular base frame connected to an approximately rectangular lifting frame by scissors legs, themselves connected by a centre shaft, the lifting frame being further provided with a seat and an adjustable backrest, and a device to stabilize the base frame on the floor. Figure 1 shows a side view of the device of the invention, lifted vertically from the lowest sitting position for the operator. Figure 2 is the same view as figure 1 , in the lowest sitting position.

Figure 3 is a view from above of the device of the invention. Figure 4 illustrates the device of the invention viewed from the underside. Figure 5 illustrates the device of the invention viewed from the front and adjusted in a sitting position for the operator. Figure 6 illustrates the design of the lifting arm.

The device of the invention consists of a chassis composed of a rectangular base frame 1 and a corresponding lifting frame 2. The base frame 1 is equipped with castors 3 placed in the vicinity of the four corners of the base frame 1. The castors 3 are mounted on one side of the base frame 1 and protrude from it in such a manner as to permit the base frame 1 to be displaced horizontally on a floor with the help of said castors 3. The castors can swivel around a horizontal axis and a vertical axis so that the base frame 1 can be displaced on the floor as easily as possible.

Mounted on one of the short sides of the rectangular base frame 1, and approximately in the same plane as said frame, is a handle 4. Out of the opposite short side of the base frame 1 , and in the prolongation of the plane formed by said base frame 1, two transport wheels 5 are mounted in the vicinity of the two closest corners of the base frame 1. These two wheels 5 swivel around a horizontal axis.

The base frame 1 and the lifting frame 2 are connected to each other by a lifting device which consists of a first scissors leg 6 and a second scissors leg 7 provided between the frames 1,2 and arranged so as to be actuated and thus displace the two frames 1,2 away from each other. The first scissors leg 6 swivels around a first axle 8 relative to the base frame 1. It is mounted on the base frame 1 close to the short side of the base frame 1 where the transport wheels 5 are situated, and positioned between the two longest sides of the base frame 1. The opposite extremity of the first scissors leg 6 is mounted so as to slide on the lifting frame 2, sliding against the half of the lifting frame 2 which is situated furthest away from the securing point of the first scissors leg 6 to the base frame 1, so as to form a diagonal in the space between the two frames 1,2.

The second scissors leg 7 is mounted on a third axle 8' situated on the lifting frame 2 close to the short side of said lifting frame 2 which is closest to the short side of the base frame 1 where the transport wheels 5 are positioned. The opposite extremity of the second scissors leg 7 is mounted so as to slide on the base frame 1 , sliding against the half of the base frame 1 which is furthest away from the securing point of the second scissors leg 7 to the lifting frame 2. At the point where the first scissors leg 6 and the second scissors leg 7 cross in the space between the frames 1,2, said scissors legs 6,7 are connected to one another so as to swivel around a centre shaft 9.

The lifting device 6,7,9 will displace the base frame 1 away from the lifting frame 2 with a vertical force. This force is produced by a manual hydraulic lifting cylinder 10 mounted so as to swivel from one extremity on the side of the base frame 1 to which the handle 4 is mounted. The opposite extremity of the lifting cylinder 10 is secured to an approximately L-shaped lifting arm 11. The L-shape has, in addition to its own short arm 11 ', a corresponding short arm 11 ' parallel to the first, but slightly higher up along the long arm. The longest arm of the L-shape is wedge-shaped. The short arms 11' are turned towards the base frame 1 and the short arm 11 ' which is situated at the extremity of the long arm is mounted at its free extremity to the extremity of the lifting cylinder 10 which is not connected to the side of the base frame 1, in such a manner as to swivel around a lifting axle 11". On the base frame 1, and vertically situated under the centre axle 9 is a wheel 25, and further between the axle is a guide bar 24. Against it lies the wedge- shaped extremity of the lifting arm 11. Mounted on the extremity of the second scissors leg 7 which slides on the base frame 1 is a slide shaft 12 which is always situated between the two short arms 11'. When the lifting frame 2 is resting against the base frame 1 and the lifting device 6,7,9 is most spread out, and when the lifting cylinder 10 is about to initiate elevation of the lifting frame 2 from the base frame 1, the lifting device must come out of a resting position before it starts operating. The first part of the movement of the lifting cylinder 10 will push the wedge-shaped part of the lifting arm 11 between the guide bar 24 and the centre axle 9 in order to move the lifting device out of its resting position and to subsequently lift that point. The slide shaft 12 will at first be situated against the inner short arm 11' on the long arm of the L-shape. When the lifting cylinder 10 initiates its displacement and the wedge shape goes under the centre axle 9, the slide shaft 12 remains immobile until the second short arm 11' reaches it and takes it along in its movement. When the second short arm 11' reaches the slide shaft 12, the lifting device is out of its resting position. When the lifting device 6,7,9 is out of its resting position, the outer short arm 11' will act on the slide shaft 12 so as to pull said shaft and the extremity of the second scissors leg 7 towards the second axle 8. The lifting device 6,7,9 starts lifting, operating much like a pair of scissors. When the lifting device has left its resting position, the force of the lifting cylinder 10 will act directly on the lifting device in order to close the latter by acting on the second scissors leg 7. When the slide shaft 12 rests against the outer short arm 11', the guide bar 24 is held in place by the slide shaft 12 during the remainder of the lifting operation. When the lifting device resumes its resting position, the slide shaft 12 will be in the position indicated on figure 6.

Under the fixed seat 13 is a power unit which is used to actuate the lifting cylinder 10. It consists of a pump 20 actuated with the help of a pump arm 21. The pump arm 21 is operated by up-and-down movements and increases the pressure in the lifting cylinder 10. A pressure reducing valve 19 is provided for releasing the pressure in the lifting cylinder 10 and lowering the lifting frame 2.

The face of the lifting frame 2 which is turned away from the base frame 1 is provided with two cushions. One of the cushions constitutes a seat 13 which is inclined towards the lifting frame 2, at an angle from the side where the second axle 8 is situated, going down towards the middle of the lifting frame 2. In the vicinity of the latter end of the seat 13 a backrest 14 is provided which stretches in the direction of and beyond the edge of the lifting frame 2 which is opposite the seat 13 end. The extremity of the backrest 14 which is closest to the seat 13 can swivel around a horizontal chair axle 15 so that the backrest 14 can be lifted at an angle with the lifting frame 2, and form with the seat 13 a chair with an adjustable back. On each side of the lifting frame 2, on the side closest to the base frame 1, U- shaped brackets 16 are provided. A lockable gas cylinder, the back lift 17, is mounted in each of these brackets 16, and in a manner enabling it to swivel, while the opposite extremity of the back lifts 17 is mounted to the back of the backrest 14 where it also can swivel, at a distance approximately two thirds of the backrest 14 length from the chair axle 15.

The back lift 17 is a gas reducer. In the vicinity of the chair axle 15, a release device 18 is provided, which can be pulled out, and actuate the back lift 17 which then lifts the backrest 14 to the desired angle. When that angle is reached, the releasing device 18 can lock the backrest 14 in the chosen position. The backrest 14 is somewhat wider than the lifting frame 2 from the space for the shoulders and down towards the space for the hips of the operator, and its cross section is somewhat incurved. This is achieved with the help of raised sides 14' aiming to give good lateral support to the back, and to provide adequate support for parts of the operator's arms from shoulder to hand while working. Furthermore, the backrest 14 has an elongated design under the neck and head for the benefit of the operator. A headrest 22 can be rotated to various positions in order to provide the correct height under the neck and head.

Next to the seat 13 a space is provided for a tray or a box 23 for containing tools or the like which the operator may need to have within easy reach while working. When the box 23 is not in use, it is positioned in the prolongation of the lifting frame 2, under the backrest 14. Two sets of stabilizers 26 are provided on the base frame 1. One set of stabilizers 26 is situated on the base frame 1 next to the castors 3 which are closest to the handle 4. The second set of stabilizers 26 is mounted between the transport wheels 5 and the adjacent castors 3. In the preferred embodiment of the invention, the stabilizers 26 are made of hydraulic cylinders. These are connected to the same hydraulic system as the lifting cylinder 10. By operating the pump arm 21, the stabilizers 26 can either be lowered onto the floor and the base frame 1 is stabilized on the floor, or the lifting cylinder 10 is actuated to lift the lifting frame 2. A reversing switch (not illustrated on the figures) connected to the hydraulic system enables the pump arm 21 to actuate either the stabilizers 26 or the lifting cylinder 10. The circuit which, at any given moment, is not connected to the lifting cylinder 10 will be closed off and the pressure maintained. With the help of the pressure reducing valve 19 and the reversing switch in the correct position, either the stabilizers 26 are lifted up and stabilizing ends, or the lifting frame 2 is lowered.

The hydraulic system is also equipped with a safety device which releases the pressure if the lifting frame 2 is subjected to a weight in excess of the set limit value (e.g. 120 kg), and the lifting frame will then lower itself (Health, Environment and Safety Measures). The set limit value is adjustable.

As illustrated on figure 1, the present invention is also provided with an inclined seat 13 in order to ensure that the operator has a safe sitting position. Moreover, the seat 13 and the backrest 14 are incurved in order to provide lateral stability. All functions of the device which the operator needs when using the device can be reached when the user is sitting on the seat 13. This means that the user can sit down on the seat 13 and roll the device under a vehicle. The device can then be operated with easy movements and manoeuvres to bring the lifting frame 2 in the correct position, the backrest 14 at the correct angle, place the headrest 22 in the desired position and stabilize the whole device on the floor. When the user wishes to displace the device on the floor, the stabilizers 26 can be lifted and the user O97/00058

displaces the device with his feet, subsequently stabilizing the device into the new desired place. All this can be effected from the user's place on the device, regardless of the position of the lifting frame 2 and of whether the user is sitting or lying down on the device.

Claims

1. Device to provide a correct working position, a garage creeper consisting of a frame equipped with castors (3), a backrest (14) and a headrest (22), characterized by an approximately rectangular base frame (1) connected to an approximately rectangular lifting frame (2) with the help of scissors legs (6,7) connected by a centre shaft (9), the lifting frame (2) being provided with a seat (13) and an adjustable backrest (14) and a device (26) for stabilizing the base frame

(1) on the floor.

2. The device to provide a correct working position of the previous claim, characterized i n th at a first scissors leg (6) is mounted, swivelling on a first axle (8), on the base frame (1), in the vicinity of one of the base frame's (1) short sides, while the opposite extremity of the first scissors leg (6) is sliding on the half of the lifting frame (2) which is furthest away from the mounting point of the first scissors leg (6) to the base frame (1), and a second scissors leg (7) is mounted, swivelling on a third axle (8'), near the lifting frame's

(2) short side which is closest to the first axle (8), while the opposite extremity slides against the half of the base frame (1) which is furthest away from the mounting point of the second scissors leg (7) to the lifting frame (2), both the first scissors leg (6) and the second scissors leg (7) being fastened to each other with the help of a centre shaft (9) around which they swivel at their crossing point.

3. The device to provide a correct working position of the previous claims, characterized in that at the extremity of the second scissors leg

(7) which slides against the base frame (1) a slide shaft (12) is mounted, positioned between the two short arms (IT) of an approximately L-shaped lifting arm (11), the longest arm of the L being wedge-shaped and resting between a guide bar (24) and the centre shaft (9), while one extremity of a lifting cylinder (10) is connected to the outer short arm (IT) of the L-shape, and its opposite extremity to one of the base frame's (1) short sides. 4 The device to provide a correct working position of claim 3, characterized in that the lifting cylinder (10) is connected to a pneumatic pump (20) with a pump arm (21) mounted on the lifting frame (2) in the vicinity of the third axle (8')

5 The device to provide a correct working position of claim 1, char cterized in that a seat (13) is provided starting from the short side of the lifting frame (2) where the third axle (8') is situated, and continuing at an angle towards the centre of the lifting frame (2), and starting from the place where the seat (13) ends a backrest (14) is mounted and equipped with a headrest (22)

6 The device to provide a correct working position of the previous claim, characterized in that the extremity of the backrest (14) which is situated closest to the seat (13) is mounted on the lifting frame (2) and able to swivel around a chair axle (15), while U-shaped brackets (16) are mounted on the long sides of the lifting frame (2), and back lifts (17) are mounted to and can swivel on one extremity of said brackets (16) while the opposite extremity of the back lifts (17) is mounted to and can swivel on the backrest (14)

7 The device to provide a correct working position of claim 1, c h a r a c- terized by a handle (4) and transport wheels (5)

8 The device to provide a correct working position of claim 1, characterized by pairs of stabilizers (26) mounted on the base frame (1) close to the pairs of castors (3)