GB2106068A - Overhead travelling cranes - Google Patents

Abstract

Mobile machine apparatus (5) is described comprising a first machine part displaceable along a first path (9) and a second machine part 11 connected to the first part but displaceable along a second path. Sensing means (12) are further provided to sense at least two limits of relative position between the first part and the second part 11 and displace one of the parts to maintain the parts within the limits. In the preferred embodiment described the first part comprises hydraulic press activating means and the second part 11 comprises a pressing head. <IMAGE>

Description

SPECIFICATION Improvement in or relating to mobile machinery This invention relates to mobile machinery and has been developed particularly, though not necessarily solely to provide a mobile overhead assembly for press fabrication.

It is an object of the present invention to provide mobile machinery and/or a method of providing an item of mobile machinery which will at least provide the public with a useful choice.

Accordingly, in one aspect, the invention consists in mobile machine apparatus comprising a first machine part movable along a first path; a second machine part connected to said first machine part and movable along a second path; displacement means to, in use, move said first or said second machine part along its respective path; and sensing means constructed and arranged to sense at least two limits of relative position of said first and second parts and operate said displacement means to maintain the relative positions of said first and second machine parts at or between said limits.

In a second aspect the invention consists in a mobile overhead press assembly comprising press actuating means movable along a first overhead path; displacement means to move said press actuating means along said first path; a pressing head connected to said actuating means, said pressing head being suspended from and movable along a second overhead path; and sensing means constructed and arranged to sense at least two limits of relative position between said press actuating means and said pressing head and operate said displacement means so as to maintain the relative positions of said press actuating means and said means and said pressing head at or within said limits.

In a third aspect the invention consists in a method of providing an item of mobile machinery, said method comprising the steps of mounting a first machine part for movement along a first path; mounting a second machine part connected to said first machine part for movement along a second path; providing displacement means to displace one of said first or second machine parts along its respective path; and providing sensing means to sense at least two limits of relative position of said first and second machine parts and operate said displacement means to maintain said first and second parts at or within said limits.

To those skilled in the art to which this invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and it is not our intention to limit the scope of the invention by those disclosures and descriptions, or otherwise, than by the terms of the appended claims.

The invention consists in the foregoing and also envisages constructions of which the following gives examples.

One preferred form of the invention, as applied to an overhead mobile assembly for press fabrication, will now be described with reference to the accompanying drawings in which: Figure 1 shows a plan view, from above, of apparatus according to the invention; and Figure 2 shows a side elevational view of the apparatus shown in Figure 1.

Referring to the drawings, according to the invention there is provided mobile machine apparatus 5 which, in the form shown, comprises an overhead mobile pressing assembly designed particularly for use in pressing toothed nail connector plates into timber to form prefabricated structural trusses 6. To this end the apparatus must be capable of ready movement over all points of a pressing table 7 on which the trusses 6 are formed.

As shown, the apparatus comprises a first machine part or press actuating means 8 moveable along a first path which, in the embodiment illustrated, is defined by an I section steel beam 9. The beam 9 is, in use, mounted in the roof structure of a building and thus provides a track along which the press actuating means 8 may be displaced. A motor 10 is as shown, provided in unit with the press actuating means 8, the motor 10 driving a wheel or gear (not shown) in contact with the beam 9 to effect displacement of the press actuating means along the beam 9.

The apparatus further includes a second machine part or pressing head 10 which is attached to the part 8 and is moveable along a second path and sensing means 12 which are constructed and arranged to sense at least two limits of relative position, indicated in dotted outline in Figure 1, between the actuating means 8 and the pressing head 11 and, upon doing so, operating the motor 10 to move the actuating means 8 so as to maintain the relative position between the actuating means 8 and the pressing head 11 at or between the two limits.

As shown the press actuating means 8 and the pressing head 10 are connected by an arm 13 which is pivotly mounted on the unit carrying the actuating means 8 at 14 and extends out so as to, in use, sweep over the area immediately above the pressing table 7. The outer end of the arm 13 is vertically supported by means of a link 15, the upper end of which is slidable along a further beam 16 also, in use, mounted in the roof structure of the building housing the apparatus. The link 15 is preferably at least partially flexibie to accomodate the radial movement which occurs as the arm 13 pivots about pivot point 14.

The pressing head 11 is suspended from the arm 13 by means of a chain or other link 17 which includes a connection 18 at the upper end thereof.

The connection 18 is preferably such as will allow the link 17 and thus the pressing head 11 to slide longitudinaly of the arm 13. The construction and arrangement of the link or cabin 17 or the connections at either end thereof, is such that the pressing head 11 may freely swivel or pivot about the axis thereof. Thus by moving the entire apparatus 5 longitudinally of the beams 9 and 16, or by moving the pressing head 11 longitudinally of the arm 13, or by swivelling the pressing head 11 about the axis of the link 17 the pressing head 11 may be positioned at any desired point over the pressing table 7. It will be appreciated, therefore, that the second path is a combination of a number of linear components.

The sensing means 12 preferably comprise a pair of limit switches, mounted in unit with the actuating means 8 and motor 10, which sense the relative positions between the actuating means 8 and the pressing head 11 by sensing the angular displacement between the arm 13 and the unit bearing the actuating means 8. The arm 13 is provided with an extension 19 on the inner end thereof which engages one of the limit switches 12 at a limit position and actuates the motor 10 to move the actuating means in such a direction along the beam 9 as will tend to keep the extension 19 on or between the limit switches. Afurther limit switch 12a is, as shown, provided mid way between the switches 12 to stop the motor 10 when the arm 13 is substantially perpendicular to the beam 9.

In the form of apparatus shown, the pressing head 11 comprises a C clamp having a plunger 20 operated by hydraulic cylinder 21. The actuating means 8 thus comprises a hydraulic pump fed from a suitable hydraulic reservoir which feeds the cylinder 21 by means of hydraulic lines 22.

In use, the operator positions the pressing head 11, which is of relatively low mass, manually by grasping the pressing head 11 and moving it towards the desired position. The pressing head may be thus moved longitudinally over the table 7 and transverse thereto. As the pressing head 11 is moved longitudinally over the pressing table 7 the arm 13 is displaced about pivot point 14 until extension 19 on the arm 13 engages one of the limit switches 12. The motor 10 is the actuated to displace the actuating means 11 along the beam 9 in such a direction as will maintain the relative position between the actuating means 8 and the pressing head 11 i.e. the actuating means 8 follows the pressing head 11. Movement of the actuating means 8 continues until extension 19 engages limit switch 1 2a.If the pressing head 11 is to be positioned transversely of the table 7 this can be affected by manually sliding the pressing head 11 along the arm 13. Once located in the desired position, the pressing head 11 is actuated in the conventional manner.

It will be appreciated, by those skilled in the art that in apparatus of thins type the mass of the motor 10 and the actuating means 8 is relatively high when compared to the mass of the pressing head 11. By splitting the apparatus into two parts, one of relatively high mass and one of relatively low mass and making the part of relatively high mass self powering, the task of the operator is made much easier.

Further the jerky action experienced when a suspended, heavy mass is displaced, is obviated or minimised in the present apparatus as that part which is suspended i.e. the pressing head 11 is of relatively low mass.

While the particularform of apparatus described herein has been designed for use in pressing operation it will be appreciated that the invention could be applied to other forms of apparatus.

Claims (18)

1. Mobile machine apparatus comprising a first machine part movable along a first path; a second machine part connected to said first machine part and movable along a second path; displacement means to, in use, move said first or said second machine part along its respective path; and sensing means constructed and arranged to sense at least two limits of relative position of said first and second parts and operate said displacement means to maintain the relative positions of said first and second machine parts at or between said limits.

2. Apparatus as claimed in claim 1 wherein said second machine part is attached to an arm, said arm being pivotal about a point fixed with respect to said first machine part.

3. Apparatus as claimed in claim 2 wherein said second machine part is displaceable along said arm.

4. Apparatus as claimed in claim 2 or claim 3 wherein said sensing means is constructed and arranged to sense limits of angular displacement of said arm.

5. Apparatus as claimed in claim 4 wherein said sensing means comprise limit switches.

6. Apparatus as claimed in any one of the preceding claims further including mearis to define said first path.

7. Apparatus as claimed in claim 6 wherein said means to define said first path comprises a track.

8. Apparatus as claimed in claim 7 wherein said displacement means comprises a motor driven wheel or gear mounted in unit with said first machine part and engaged with the said track.

9. A mobile overhead press assembly comprising press actuating means movable along a first overhead path: displacement means to move said press actuating means along said first path; a pressing head connected to said actuating means, said pressing head being suspended from and movable along a second overhead path; and sensing means constructed and arranged to sense at least two limits of relative position between said press actuating means and said pressing head and operate said displacement means so as to maintain the relative positions of said press actuating means and said pressing head at or within said limits.

10. An assembly as claimed in claim 9 wherein said press actuating means comprises a tank for hydraulic fluid and a hydraulic pump.

11. An assembly as claimed in claim 9 or claim 10 wherein said pressing head comprises a hydraulically operated C-clamp.

12. An assembly as claimed in any one of claims 9 to 11 including an arm pivotally mounted with respect to said press actuating means, said pressing head in turn being suspended from said arm.

13. An assembly as claimed in claim 12 wherein said pressing head is movable longitudinally of said arm.

14. A method of providing an item of mobile machinery, said method comprising the steps of mounting a first machine part for movement along a first path; mounting a second machine part con nected to said first machine part for movement along a second path; providing displacement means to displace one of said first or second machine parts along its respective path; and providing sensing means to sense at least two limits of relative position of said first and second machine parts and operate said displacement means to maintain said first and second parts at or within said limits.

15. A method as claimed in claim 14 wherein said first and said second machine parts are mounted in the roof structure of a building.

16. Mobile machine apparatus when constructed, arranged and operable substantially as hereinbefore described with reference to the accompanying drawings.

17. A mobile overhead press assembly when constructed arranged and operable substantially as hereinbefore described with reference to the accompanying drawings.

18. A method of providing an item of mobile machinery substantially as hereinbefore described with reference to the accompanying drawings.