GB1560125A

GB1560125A - Load handling device

Info

Publication number: GB1560125A
Application number: GB46691/77A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1976-11-12
Filing date: 1977-11-09
Publication date: 1980-01-30
Also published as: FR2394363B1; DE2750135A1; SE400539B; FI67830C; NO145374B; FI773270A; FR2394363A1; NO773777L; NO145374C; FI67830B

Description

(54) AN IMPROVED LOAD HANDLING DEVICE (71) I, KNUT OLOVFRISK, a Swedish subject of N. Gaevlevaegen 41, 810 40 Hedesunda, Sweden, do hereby declare the invention, for which I pray that a patent may be granted to me and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a load handling device which has a lifting arm including a parallelogram linkage. The movement of the lifting arm is controlled by two adjacent joints of the parallel linkage being connected to a vertical guide and a horizontal guide respectively. In this way, the horizontal and the vertical movement of the two joints results in a proportional and corresponding movement of the free, load carrying end of the lifting arm.

Load handling devices of this kind are often used to support the weight of and lift a workpiece to enable an operator to move the workpiece into a predetermined position to enable it to be machined. For this type of work, during a particular production run a number of similar workpeices will be brought to a particular machine tool and it is required that they all be put into the same position with respect to the machine tool. However, at the end of this production run the machine tool will have to accept further, different workpieces and these may need to be positioned in a different place with respect to the machine.

According to this invention a load handling device comprises a lifting arm including a papallelogram linkage, two adjacent joints of which are connected to a vertical guide and a horizontal guide respectively, to control the movement of the lifting arm, horizontal and vertical movement of the two joints resulting in a proportional and corresponding movement of the free, load carrying end of the lifting arm, and adjustable stop means associated with at least one guide to limit, in use, the movement of its respective joint to enable the lifting arm to be moved readily into at least one predetermined position, the stop means including a slot in a support plate carrying the guide, and at least one limit stop associated with the slot, the arrangement being such that, in use, the limit stop is movable along the slot and lockable into position to determine the extent of movement of joint along the guide and hence of the lifting arm.

With load handling device in accordance with this invention, the position to which the workpiece is brought may be varied by adjusting the stop means and, once adjusted the workpiece will always be brought to the same position until the stop means are readjusted and, in this way, the stop means may be arranged as easily as the margins on a typewriter.

Preferably, the stop means are associated with each of the guides to limit both the vertical and the horizontal movement of the lifting arm. The or each stop means preferably includes two limit stops, to limit the extent of movement to that in between the two stops, so that, in use, the lifting arm is readily movable between two predetermined positions.

Preferably, the parallelogram linkage is arranged so that a small movement of the two joints along the horizontal and vertical guides results in a much larger displacement of the free, load carrying end of the lifting arm. In this way, the stop means may be arranged within a relatively small area but still be effective to control the movement of the lifting arm when this takes place over a much larger area.

The load handling device may be arranged so that movement in one direction, usually the horizontal direction, is carried out manually, whereas movement in the other direction, usually the vertical direction, is controlled by an operator but the power for such movement comes from a power-operated actuator. In this case, the stop means asso ciated with the horizontal guide may have the form of simple mechanical abutments which physically limit the movement of the connection between the lifting arm and the horizontal guide, whereas the stop means associated with the vertical guide is arranged to control the power supplied by the poweroperated actuator.

A particular example of a load handling device in accordance with this invention will now be described with reference to the accompanying drawing which is a diagrammatic side elevation.

The load handling device comprises a lifting arm having a handling arm 1 supported by a parallelogram linkage. The handling arm 1 carries a control head 2 and a control lever 3. The control lever controls the operation of a power-operated actuator which, in this example, is a hydraulic piston and cylinder assembly 4. The piston rod of the hydraulic piston and cylinder assembly 4 is connected to the connection between an extension 6 of one link of the parallelogram linkage and a pair of vertical guide rails 8 and 9.

The hydraulic piston and cylinder assembly 4 provides the power for the vertical component of the lifting of any load carried by the handling arm 1. A joint 5 of the parallelogram linkage is connected to the rails 8 and 9 through the extension 6. The guide rails 8 and 9 are carried by a support plate 10 and a slot 11, which is located between the guide rails 8 and 9 and parallel to them, is provided in the support plate 10. A carriage 26 is arranged to slide up and down along the slot 11 and this is also connected to the end of the extension piece 6 by a connection 7.

Adjustable stops 14 and 15 which each include a cam surface slide along the carriage 26. The stops may be locked in any position along the carriage 26 by knobs 12 and 13. A pair of electrical limit switches 16 and 17 are fixed onto the support plate 10 and arranged beside the slot 11. The cam surfaces on the stops 14 and 15 are arranged to engage the switches 16 and 17 and actuate them. The switches 16 and 17 are arranged to control the power supplied to the hydraulic piston and cylinder assembly 4 and thus the position of the stops 14 and 15 govern the extent of movement in a vertical direction of the lifting arm.

A joint 18 of the parallelogram linkage is connected to a horizontal guide formed by the guide rails 19 and 20 which are also connected to the support plate 10. Horizontal movement of a load carried by the handling arm 1 takes place manually and the horizontal movement is controlled by the connection between the joint 18 and the guide rails 19 and 20. A slot 21 in the support plate 10 is arranged in between the guide rails 19 and 10 and parallel to them. Two stops 22 and 23 are arranged to slide backwards and forwards along the slot 21 and arranged so that they can be locked in any position along the slot 21 by handles 24 and 25.The extent of horizontal movement of the joint 18 is thus determined by the position of stops 22 and 23 and, in this way the extent of horizontal movement of the free end of the load handling arm 1 is also determined by the position of the stops 22 and 23.

Thus, by adjusting the positions of the stops 14 and 15 and the stops 22 and 23, it is possible to ensure that a series of workpeices are readily and consistently moved between two predetermined positions so that the load handling device can be set up to transfer workpieces between these two positions and will always place the workpieces in exactly the same position. However, the positions between which workpieces are moved may be adjusted easily and conveniently by merely moving the positions of the stops 14, 15, 22 and 23.

WHAT I CLAIM IS: 1. A load handling device comprising a lifting arm including a parallelogram linkage, two adjacent joints of which are connected to a vertical guide and a horizontal guide respectively, to control the movement of the lifting arm, horizontal and vertical movement of the two joints resulting in a proportional and corresponding movement of the free, load carrying end of the lifting arm, and adjustable stop means associated with at least one guide to limit, in use, the movement of its respective joint to enable the lifting arm to be moved readily into at least one predetermined position, the stop means including a slot in a support plate carrying the guide, and at least one limit stop associated with the slot, the arrangement being such that, in use, the limit stop is movable along the slot and lockable into position to determine the extent of movement of joint along the guide and hence of the lifting arm.

2. A load handling device according to claim 1, in which stop means are associated with each guide to limit both the vertical and horizontal movement of the lifting arm.

3. A load handling device according to claim 1 or claim 2, in which the or each stop means includes two limit stops to limit the extent of movement of the joint or joints to that in between the stops, so that, in use, the lifting arm is readily movable between the two predetermined positions.

4. A load handling device according to any one of the prededing claims, which also includes a power-operated actuator arranged to act upon the connection between the lift ing arm and the vertical guide, the arrange ment being such that, in use, the power operated actuator lifts the load carried by the lifting arm..

5. A load handling device according to claim 4, in which a carriage is arranged to

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. ciated with the horizontal guide may have the form of simple mechanical abutments which physically limit the movement of the connection between the lifting arm and the horizontal guide, whereas the stop means associated with the vertical guide is arranged to control the power supplied by the poweroperated actuator. A particular example of a load handling device in accordance with this invention will now be described with reference to the accompanying drawing which is a diagrammatic side elevation. The load handling device comprises a lifting arm having a handling arm 1 supported by a parallelogram linkage. The handling arm 1 carries a control head 2 and a control lever 3. The control lever controls the operation of a power-operated actuator which, in this example, is a hydraulic piston and cylinder assembly 4. The piston rod of the hydraulic piston and cylinder assembly 4 is connected to the connection between an extension 6 of one link of the parallelogram linkage and a pair of vertical guide rails 8 and 9. The hydraulic piston and cylinder assembly 4 provides the power for the vertical component of the lifting of any load carried by the handling arm 1. A joint 5 of the parallelogram linkage is connected to the rails 8 and 9 through the extension 6. The guide rails 8 and 9 are carried by a support plate 10 and a slot 11, which is located between the guide rails 8 and 9 and parallel to them, is provided in the support plate 10. A carriage 26 is arranged to slide up and down along the slot 11 and this is also connected to the end of the extension piece 6 by a connection 7. Adjustable stops 14 and 15 which each include a cam surface slide along the carriage 26. The stops may be locked in any position along the carriage 26 by knobs 12 and 13. A pair of electrical limit switches 16 and 17 are fixed onto the support plate 10 and arranged beside the slot 11. The cam surfaces on the stops 14 and 15 are arranged to engage the switches 16 and 17 and actuate them. The switches 16 and 17 are arranged to control the power supplied to the hydraulic piston and cylinder assembly 4 and thus the position of the stops 14 and 15 govern the extent of movement in a vertical direction of the lifting arm. A joint 18 of the parallelogram linkage is connected to a horizontal guide formed by the guide rails 19 and 20 which are also connected to the support plate 10. Horizontal movement of a load carried by the handling arm 1 takes place manually and the horizontal movement is controlled by the connection between the joint 18 and the guide rails 19 and 20. A slot 21 in the support plate 10 is arranged in between the guide rails 19 and 10 and parallel to them. Two stops 22 and 23 are arranged to slide backwards and forwards along the slot 21 and arranged so that they can be locked in any position along the slot 21 by handles 24 and 25.The extent of horizontal movement of the joint 18 is thus determined by the position of stops 22 and 23 and, in this way the extent of horizontal movement of the free end of the load handling arm 1 is also determined by the position of the stops 22 and 23. Thus, by adjusting the positions of the stops 14 and 15 and the stops 22 and 23, it is possible to ensure that a series of workpeices are readily and consistently moved between two predetermined positions so that the load handling device can be set up to transfer workpieces between these two positions and will always place the workpieces in exactly the same position. However, the positions between which workpieces are moved may be adjusted easily and conveniently by merely moving the positions of the stops 14, 15, 22 and 23. WHAT I CLAIM IS:

1. A load handling device comprising a lifting arm including a parallelogram linkage, two adjacent joints of which are connected to a vertical guide and a horizontal guide respectively, to control the movement of the lifting arm, horizontal and vertical movement of the two joints resulting in a proportional and corresponding movement of the free, load carrying end of the lifting arm, and adjustable stop means associated with at least one guide to limit, in use, the movement of its respective joint to enable the lifting arm to be moved readily into at least one predetermined position, the stop means including a slot in a support plate carrying the guide, and at least one limit stop associated with the slot, the arrangement being such that, in use, the limit stop is movable along the slot and lockable into position to determine the extent of movement of joint along the guide and hence of the lifting arm.

slide along the slot associated with the vertical guide and is connected to the connection between the vertical guide and the lifting arm so that the carriage is moved along the slot as the connection moves along the guide, the carriage carrying the limit stop or stops, and the stop means also includes electrical limit switches fixed to the support plate beside the slot and connected to a control circuit for the power actuator, the arrangement being such that the limit stops engage the electrical limit switches to control the extent of movement of the power-operated actuator.

6. A load handling device according to claim 5 in which the limit stops include a cam surface to engage and operate the electrical limit switches and in which the limit stops are slidable along the carriage and lockable into predetermined positions with respect to the carriage.

7. A load handling device according to claim 1, constructed substantially as described with reference to the accompanying drawings.