GB2049614A

GB2049614A - Linear lifting and lowering mechanism

Info

Publication number: GB2049614A
Application number: GB7905257A
Authority: GB
Original assignee: MCGUIRE BROS ENG PROJECTS Ltd
Current assignee: MCGUIRE BROS ENG PROJECTS Ltd
Priority date: 1979-02-14
Filing date: 1979-02-14
Publication date: 1980-12-31

Abstract

A lift mechanism, especially for lowering and lifting work-pieces or carrier means therefor into and out of processing tanks, e.g. in degreasing operations, provides for linear or substantially linear vertical lifting and lowering movements and broadly comprises a lift arm (16) pivotted (15) at one end, the other end (16a) whereof being adapted for the attachment thereto of a load, e.g. a work-piece or work-piece carrier means. Means (22) are provided for effecting angular displacement of said lift arm (16) and further means, e.g. a link pivotted at a fixed point (25) for displacing its pivot (15) as it is angularly displaced whereby the load carry end (16a) is constrained to effect linear or substantially linear vertical movements. <IMAGE>

Description

SPECIFICATION Linear lifting and lowering mechanism This invention relates to linear lifting and lowering mechanism more particularly, but not exclusively, for use in moving work-pieces into and out of pro cessing tanks, e.g. in the carrying out of degreasing operations.

Means for effecting a straight lowering and lifting of work-pieces into and out of processing tanks are of course known but heretofore usually comprise chains or/and slides which are expensive to construct and install and require considerable maintenance in view of their multiplicity of moving parts and their disposition above volatile solvents.

The present invention has for its object to provide a simple, but effective, compact lever and linkage system only a minor part of which needs to be above a processing tank, which enables a full use of the tank to be made, which is of robust construction embodying a minimum of moving parts, and which will require only a minimum of attention to maintain same in efficient working order.

Broadly, according to the invention, a linear lifting and lowering mechanism comprises an arm (hereinafter referred to as a "lift arm") pivotted at one end and the other end whereof is adapted for attachment to a load, e.g. a work-piece or work-piece carrier, means operable to effect angular displacement of said lift arm about its pivot, and means for displacing said pivot as the lift arm is angularly displaced whereby the load carrying end thereof is constrained to effect linear or substantially linear up vertical movements.

According to one mode of embodiment, the pivot of the lift arm is carried at one end of a second arm the other end whereof is pivotted on a fixed pivot.

Displacement of the pivot of the lift arm is effected by a link (links) pivotted at one end to said arm and the other end whereof is pivotally attached to a fixed point, the direction of pivotting of said link (links) being in the opposite sense to said lift arm. The means for effecting angular displacement of said lift arm may be a single or double acting pressure fluid operated device.

The invention is further described with the aid of the accompanying drawings which illustrate by way of example and more or less schematically one embodiment.

In said drawings, Figure lisa side elevation, Figure 2 is a front elevation, and Figure 3 is a plan view, of linear lifting mechanism according to the invention.

Referring to said drawings, X denotes a processing tank, which may be of known type, containing for example a solvent liquid into which work pieces are required to be dipped, for example for degreasing purposes. The effective area of the tank, so far as the reception of work-pieces or their carrier means is concerned, is designated Y, and therefore the lifting and lowering of the work-pieces or their carrier means must perforce be in a substantially vertical direction.

The mechanism for effecting such a linear lifting and lowering comprises a base plate 10, a pair of cheek plates 11 and a front plate 12 secured to said cheek plates and which extends above the tank X.

Pivotted on a spindle 13 between the cheek plates 11 is an upwardly extending arm 14the upper end whereof carries a bearing shaft 15 on which is pivotted the ends of a dublex lifting arm structure 16. The ends iSa of the arm structure 16 are downwardly cranked as shown and carry a transverse shaft 17 on which can be hung a work-piece (not shown) or a basket for work-pieces which requires to be lowered into the processing tank X.

The two parts of the lifting arm structure 16 each are provided with a downwardly extending lug 18, said lugs being apertured to receive a transverse shaft 19 which extends through a thrust block 20 secured to the actuating member 21 of a double acting (in this instance) pressure fluid operable device 22. The lower end of the device 22 is pivoted on a shaft 23 pivotted between the cheek plates 11. The device 22 may be pneumatically or hydraulically operated, or an air/oil system may be used.

Also pivotted on the shaft 19 on either side of the thrust block 20 are the ends of a pair of pivotal links 24 the other ends whereof are pivotted on a shaft 25 journalled in a bearing block 26 rigidly mounted at the upper end of the front plate 12.

It will be clear that in use the lifting arm structure 16, in operation of the fluid operable device 22, can be moved between the position shown in full lines and that shown in broken lines. In such movement, the links 24 will pivot about the fixed shaft 25 whereby the shaft 19 extending through the lugs 18 will move though an arcuate path as indicated at "A". As a consequence the pivot point shaft 15, of the lifting arm structure 16 will be moved to the right as indicated in broken lines in Figure 1, and back again, whereby the shaft 17 carried by the lifting arm structure will move lineally (upwards or downwards) as indicated by the line "B".

In an alternative arrangement which obviates the need for the arm 14, the ends of the shaft 15 may be arranged to move within fixed horizontal guides, for example as illustrated in broken lines at 30 in Figure 3. Again, the ends of the shaft 19, or equivalent follower means associated with the lift arm 16, may be arranged to work in arcuate cam tracks in lieu of being guided by pivotal links 24.

It will be seen that the invention provides a compact, simple mechanism having relatively few moving parts, as compared with conventional straight lift mechanisms, and therefore is reliable in use needing only a minimum of maintenance and attention.

1. Linear lifting and lowering mechanisms comprising a lift arm pivotted at one end and the other end whereof is adapted for attachment to a workpiece or work-piece carrier means, means for effect

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Linear lifting and lowering mechanism This invention relates to linear lifting and lowering mechanism more particularly, but not exclusively, for use in moving work-pieces into and out of pro cessing tanks, e.g. in the carrying out of degreasing operations. Means for effecting a straight lowering and lifting of work-pieces into and out of processing tanks are of course known but heretofore usually comprise chains or/and slides which are expensive to construct and install and require considerable maintenance in view of their multiplicity of moving parts and their disposition above volatile solvents. The present invention has for its object to provide a simple, but effective, compact lever and linkage system only a minor part of which needs to be above a processing tank, which enables a full use of the tank to be made, which is of robust construction embodying a minimum of moving parts, and which will require only a minimum of attention to maintain same in efficient working order. Broadly, according to the invention, a linear lifting and lowering mechanism comprises an arm (hereinafter referred to as a "lift arm") pivotted at one end and the other end whereof is adapted for attachment to a load, e.g. a work-piece or work-piece carrier, means operable to effect angular displacement of said lift arm about its pivot, and means for displacing said pivot as the lift arm is angularly displaced whereby the load carrying end thereof is constrained to effect linear or substantially linear up vertical movements. According to one mode of embodiment, the pivot of the lift arm is carried at one end of a second arm the other end whereof is pivotted on a fixed pivot. Displacement of the pivot of the lift arm is effected by a link (links) pivotted at one end to said arm and the other end whereof is pivotally attached to a fixed point, the direction of pivotting of said link (links) being in the opposite sense to said lift arm. The means for effecting angular displacement of said lift arm may be a single or double acting pressure fluid operated device. The invention is further described with the aid of the accompanying drawings which illustrate by way of example and more or less schematically one embodiment. In said drawings, Figure lisa side elevation, Figure 2 is a front elevation, and Figure 3 is a plan view, of linear lifting mechanism according to the invention. Referring to said drawings, X denotes a processing tank, which may be of known type, containing for example a solvent liquid into which work pieces are required to be dipped, for example for degreasing purposes. The effective area of the tank, so far as the reception of work-pieces or their carrier means is concerned, is designated Y, and therefore the lifting and lowering of the work-pieces or their carrier means must perforce be in a substantially vertical direction. The mechanism for effecting such a linear lifting and lowering comprises a base plate 10, a pair of cheek plates 11 and a front plate 12 secured to said cheek plates and which extends above the tank X. Pivotted on a spindle 13 between the cheek plates 11 is an upwardly extending arm 14the upper end whereof carries a bearing shaft 15 on which is pivotted the ends of a dublex lifting arm structure 16. The ends iSa of the arm structure 16 are downwardly cranked as shown and carry a transverse shaft 17 on which can be hung a work-piece (not shown) or a basket for work-pieces which requires to be lowered into the processing tank X. The two parts of the lifting arm structure 16 each are provided with a downwardly extending lug 18, said lugs being apertured to receive a transverse shaft 19 which extends through a thrust block 20 secured to the actuating member 21 of a double acting (in this instance) pressure fluid operable device 22. The lower end of the device 22 is pivoted on a shaft 23 pivotted between the cheek plates 11. The device 22 may be pneumatically or hydraulically operated, or an air/oil system may be used. Also pivotted on the shaft 19 on either side of the thrust block 20 are the ends of a pair of pivotal links 24 the other ends whereof are pivotted on a shaft 25 journalled in a bearing block 26 rigidly mounted at the upper end of the front plate 12. It will be clear that in use the lifting arm structure 16, in operation of the fluid operable device 22, can be moved between the position shown in full lines and that shown in broken lines. In such movement, the links 24 will pivot about the fixed shaft 25 whereby the shaft 19 extending through the lugs 18 will move though an arcuate path as indicated at "A". As a consequence the pivot point shaft 15, of the lifting arm structure 16 will be moved to the right as indicated in broken lines in Figure 1, and back again, whereby the shaft 17 carried by the lifting arm structure will move lineally (upwards or downwards) as indicated by the line "B". In an alternative arrangement which obviates the need for the arm 14, the ends of the shaft 15 may be arranged to move within fixed horizontal guides, for example as illustrated in broken lines at 30 in Figure 3. Again, the ends of the shaft 19, or equivalent follower means associated with the lift arm 16, may be arranged to work in arcuate cam tracks in lieu of being guided by pivotal links 24. It will be seen that the invention provides a compact, simple mechanism having relatively few moving parts, as compared with conventional straight lift mechanisms, and therefore is reliable in use needing only a minimum of maintenance and attention. CLAIMS

1. Linear lifting and lowering mechanisms comprising a lift arm pivotted at one end and the other end whereof is adapted for attachment to a workpiece or work-piece carrier means, means for effect ing angular displacement of the lift arm about its pivot, and means for displacing said pivot as the lift arm is angularly displaced whereby the loadcarrying end thereof is constrained to effect linear or substantially linear movements.

2. Linear lifting and lowering mechanism, as claimed in claim 1, wherein the pivot of said lift arm is carried at one end of a second arm the other end whereof is pivotted on a fixed axis.

3. Linear lifting and lowering mechanism, as claimed in claim 1 or claim 2, wherein displacement of said lift arm pivot is effected by a link (links) pivotted at one end to said lift arm and at the other end to a fixed point in the direction of pivotting movement of said link (links) being in the opposite sense to said lift arm.

4. Linear lifting and lowering mechanism, as claimed in claim 1 or claim 3, wherein the pivot of said lift arm is displaceable in horizontal guide means.

5. Linear lifting and lowering mechanism, as claimed in any of claims 1, 2 or 4, wherein displacement of said lift arm pivot is effected by follower means associated with said lift arm and working in arcuate cam track means.

6. Linear lifting and lowering mechanism, as claimed in any of the preceding claims, wherein said lift arm is of duplex construction and its loadcarrying end is cranked and fitted with a transverse shaftforthe attachment of work-pieces or carrier means therefore.

7. Linear lifting and lowering mechanism, as claimed in any of the preceding claims, wherein angular displacement of said lift arm is effected by a fluid pressure operable device.

8. Linear lifting and lowering mechanism, as claimed in claims 7, wherein said fluid pressure operable device is pivotally mounted at its lower end and the actuating member thereof is associated with said lift arm.

9. Linear lifting and lowering mechanism, as claimed in any of claims 6-8, wherein the two parts of said lifting arm each is provided with a lug said lugs being apertured to carry a transverse shaft which extends through a thrust block carried by the actuating member of the fluid pressure operable device, and said pivotal links for effecting displacement of the pivot of the lift arm also are pivoted on said transverse shaft.

10. Linear lifting and lowering mechanism, subs tantial ly as herein before described with reference to the accompanying drawings.

11. A processing tank or container, with mechanism as claimed in any of the preceding claims for lowering and lifting work-pieces or carrier means therefore into and out of said tank.