GB2097717A - A vertically-operable baling press - Google Patents

Abstract

A vertically operating baling press has a press plate 1 driven mechanically via two press spindles 2, 3, the free end of each spindle 2, 3 bearing on the press plate 1 and in each case passing through a rotarily entrained spindle nut 8, 9. Each spindle nut 8, 9 is driven by a driving motor 4, 5 via a transmission line 6, 7 and the spindle nuts 8, 9 are complementary interconnected via another transmission line 10. The entire drive unit of the baling press, comprising driving motors 4, 5, transmission lines 6, 7, 10 and spindle nuts 8, 9 may be situated in the upper portion of the press housing. An electromagnetic brake which locks the motor spindle when at rest may be provided on one of the motors 4, 5. <IMAGE>

Description

SPECIFICATION Avertically-operable baling press The present invention relates to baling presses having a vertical operating position and a press plate operating from an idle position in the direction towards an operating position and driven mechanically via one one more press spindles, a free end of the one or more press spindles bearing on the press plate and in each case passing through a rotarily entrained spindle nut. Hereinafter such a press will be referred to as "of the kind described".

Various forms of baling press of the kind described have aleady been proposed, the common feature of which is that the presses must be comparatively large and bulky to provide a comparatively high press force, so that they are difficult to transport and above all cannot pass through standard doors of a height of for example 200 cms of factory premises, domestic buildings and cellar rooms. If a press force of 20 tons is required, for example, which is required to press so-called Europa pallets having a base area of 80 cms x 120 cms in one piece, a press of this kind must be made so large that it cannot pass through such standard doors.

Thus it is an object of the invention to provide a baling press of the kind described whose minimum structural height is obtained with a press capacity of 20 tons or more.

Accordingly the invention consists in a baling press of the kind described, having two press spindles the spindle nuts of which are in each driven by a driving motor via a transmission line, and wherein the spindle nuts are complementarily interconnected via another transmission line.

It is thus an essential advantage of the present invention that a press force of 20 tons is obtained with the driving system described for a pressing surface of approximately 80 x 120 cms, for pressing one-piece pressings of the order of magnitude of an Europa pallet.

Tests by the Applicants have demonstrated that the application of a single driving motor having an electric driving performance of approximately 2.2 kW results in a press capbility of approximately 7 tons. If it is intended to obtain a higher press rating, e.g. a press power of 20 tons such as required for pressing Europa pallets, the driving motor required for this purpose should be so large that the press housing as such is very bulky and the height of the press exceeds 200 cms. The driving motor may also be installed transversely; problems then arise however regarding deflection of power by means of gear trains from the horizontally running driving motor to the vertically operating spindles. A solution of this kind is also extremely expensive.

Tests have now shown that if two driving motors are utilised, of which each operates on its own press spindle, and if the press spindles are synchronised with respect to each other, the result is an exponential increase of the driving performance.

Two driving motors having an electric driving power of 2.2 kW then do not yield a press power of approximately 14 tons, but a press power of approximately 20 tons with the driving system described.

Compared to the application of a single driving motor which would have to have a power output of up to approximately 10 kW in proportion to the press capacity, an identical press power is obtained in surprising manner with two driving motors of low electric power output. In this connection, it is essential that the driving motors also operate with their driving spindles vertical and act on the corresponding spindle nut of the press spindle allocated to them via a first transmission line, e.g. via chain sprockets and a chain.

In order that the specified structural height of 200 cms is not exceeded, the entire driving unit of the baling press comprising the driving motor, transmission gears and spindle nuts, may be situated in the upper portion of the press housing. Due to the use of driving motors of comparatively low electric power output, a particularly low structural height of the driving motors results, so that the required structural height of 200 cms is not exceeded. To this end, the press spindles may pass through the top housing cover of the press housing in the upper idle position of the press plate.

If the baling press is now to be carried through doors, gates and the like which have a ground clearance of 200 cms, the press plate is first displaced from its upper idle position into its lower operating position, so that the press spindles which in the upper idle position project out of the top housing cover of the press housing, disappear within the press housing and the baling press may easily be carried through the standard doors described.

Advantageously the spindle nuts are fastened in a horizontal cross-beam secured in the press housing at both ends, via taper-roller bearings.

The said cross-beam, which is formed for example by a double-T section of double-U section beam, thus has to transmit the total press force of the press plate to the press housing. If this cross-beam is constructed as a double-T or double-U section beam, this provides the maximum mechanical loadcarrying capacity at low height, thereby again securing a contribution in obtaining a low structural height of the press housing.

In orderthatthe invention may be more clearly understood reference will now be made to the accompanying drawings illustrating merely one embodiment thereof by way of example only and in which Figure 1 shows the upper part of a press housing of a vertically operating baling press, Figure 2 shows a detail of a baling press such as is appropriate for pressing highly resilient material, Figure 3 shows a braking device in its braking position, and Figure 4 shows the braking device according to Figure 3 in its released position.

Referring now to the drawings, the upper part of the press housing of a verticaly operating baling press is shown diagrammatically in Figure 1. The press plate 1 is located between the upper idle position and a lower operating position not illustrated in detail.

The free ends of the press spindles 2, 3 each act on the press plate 1 in articulated manner via bolts 11, at bearing points arranged at a distance from each other. The press plate is thus currently entrained downwards from above vertically in the direction of the arrow 12, the idle position being the top and the thrust or operating position being at the bottom.

An extremely precise synchronous operation of the press plate 1 at a high press force of 20 tons is obtained by virtue of the parallel arrangement of two press spindles 2, 3 positioned with mutual spacing, the press force being distributed evenly over the whole press plate 1. Skewing of the press plate is thereby prevented.

To this end, the press plate 1 runs via guiding means which are not illustrated in detail, with its guiding rails 25 along the sidewalls of the press housing 13. The vertically arranged driving motors 4, 5 are fastened to the sidewalls of the press housing.

The driving spindle 14, 15 of the driving motor 4,5 is co-rotatorily coupled to a first gearwheel 16, 17 and a first chain runs over a double sprocket 17, 18. Afirst transmission line 6, 7 is thus established. Each double sprocket 17, 18 is co-rotatorily installed on the spindle nut 8, 9 allocated thereto by means of keys and of lock nuts 19 securing the keys. The second gearwheel of the double gearwheel 17, 18 is entrained by a chain drive (transmission gear 10), so that the gearwheels 17, 18 run precisely synchronously and the spindle nuts 8,9 are thereby also driven synchronously.

Tilting of the press plate 1 during the pressing operation is thus practically impossible because neither of the press spindles 2,3 can run ahead of the other because the press spindles are driven in precise synchronous rotation via the spindle nuts 8, 9. The power output of the driving motors 4,5 is thus transmitted to the spindle nuts 8,9 with high efficiency and merely under interpositioning of an uncomplicated transmission line 6, 7, 10.

Each spindle nut 8, 9 is fastened by means of taper-roller bearings 22 in a cross-beam 20 fastened to the press housing 13 at both ends, the taper-roller bearings being secured in the cross-beam 20 by means of flanges 23 and of tensioning bolts 24 traversing the flanges.

The low structural height 21 required is obtained since use is made of driving motors 4, 5 having vertically operating driving spindles 14, 15. In the upper idle position of the press plate 1 the press spindles 2, 3 pass through the housing cover 26, as shown diagrammatically, whereas they disappear in the housing cover 26 in the lower operating position of the press plate. The ends of the press spindles 2,3 protruding out of the housing cover 26 are covered by bellows not illustrated in detail.

With the construction shown, a press capacity of 20 tons is obtained successfully with two motors of a rating of 2.2 kW each, i.e. the press operates at particularly high efficiency as regards the power received and delivered.

If it is intended to press highly resilient material, the force of reaction is so great in view of the elasticity of the material pressed, that use must perforce be made of spindles which are self-locking.

This implies a much higher power demand however.

The power demand may be largely restricted if a double lead screw thread or a thread not having a self-locking action, is utilised for the press spindle according to anotherfeataure of the invention. The problem then arises however, that when the press ram has completed its stroke, i.e. when the bale has been pressed, so great a restoring force then acts on the press ram that the armatures of the press motors are entrained in the opposed direction by the press ram. The desirable pressing thrust cannot thereby be maintained however.

For presses of this kind, for which it is intended to secure maximum press forces with minimum power, a braking device, for example an electromagnetic brake which locks the motor spindle in the stopped condition may be connected to the driving spindle of the driving motor.

Thanks to this additional unit, has the additional advantages of being able to be installed after the machine as been put into use, highly resilient material such as plastics material for example may be pressed as well with large presses having low motor outputs.

One preferred embodiment is illustrated in Figure 2. One of the driving motors 4 or 5 is fitted with a braking device, being an electromagnetic brake 27 in this particular embodiment. This electromagnetic brake acts at the point at which the best speed of revolution prevails in this transmission line, so that the braking torque may be kept low.

In this connection, the actuating switch 28 of the braking device 27 may be the terminal switch of the motor for deactivation at the terminal point of the press stroke.

It is thus assured in this case that when the preset press stroke has been obtained by appropriate displacement of the terminal switch, this braking device then prevents possible turning of the motor armature in reverse direction by the press ram.

It is also possible for the actuating switch 28 of the braking device to be connected to the overload safety cutout.

In a preferred embodiment of this braking device, the electromagnetic brake 27 comprises a springloaded thrust plate 33 joined co-rotatorily to the driving spindle 14, which in its off position bears under spring loading on the brake plate 30.

Thanks to this construction, it is assured that the braking device is effective when the motor is switched off. A possible operation of the braking device with the motor switched on, is prevented thereby.

The effectiveness of the braking device may be improved moreover if a gear raising the speed of revolution of the driving spindle is fitted between the braking device 27 and the driving spindle 14.

The speed or revolution of the driving motor, for example of 1500 or 3000 revolutions, is then geared up in this case to 6000 revolutions for example, in order to be able to make use of a braking device able to manage with lesser braking forces.

It is evidently also within the ambit of the invention to make use of mechanical braking devices too, which equally and automatically lock the plate when the brake plate is at rest.

It will be apparent from Figure 3 that the brake plate 30 which is provided with a friction lining, is co-rotatorily connected to the driving spindle 14 or 15 respectively, in this embodiment of an electromagnetic brake. An electromagnet or a magnetic plate 29, is switched either on or off by the terminal switch 28 limiting the press stroke.

As an example, it is shown in Figure 3 that the driving motor 5 is swiched off by opening the switch 28. The opening of this switch 28 will commonly be performed mechanically when the press ram has reached its adjustable terminal position during pressing.

A thrust plate 33 which is also constructed as an armature for the magnetic plate 29, is pressed against the brake plate 30 by compression springs 31 upon deactivation of the magnetic flux. Guiding bolts 32 assure that no tilting occurs. Locking of the driving spindle 14 is thereby secured, i.e. the same condition is reached as that obtainable ifthetrans- mission were self-locking, although the transmission is constructed with very little frictions and the power demand during pressing is very low, therefore.

If the switch 38 is opened, the thrust plate 33 operates commensurately with the force of the compression springs 31, and the braking action is cancelled. Since the passage bores in the magnetic plate 29 and in the thrust plate 33 are formed as bearings, the spindle 14may turn freely in these bearings, without discernible frictional losses being thereby incurred.

Claims (14)

1. A baling press of the kind described, having two press spindles the spindle nuts of which are in each driven by a driving motor via a transmission line, and wherein the spindle nuts are complementarily interconnected via another transmission line.

2. A baling press as claimed in claim 1,wherein the entire drive unit of the baling press, comprising driving motors, transmission lines and spindle nuts, is situated in the upper portion of the press housing.

3. A baling press as claimed in claim 2, wherein the press spindles traverse the top housing cover of the press housing in the upper idle position of the press plate.

4. A baling press as claimed in claim 1,2 or 3, wherein the spindle nuts are secured in a horizontal cross-beam secured to the press housing at both ends, via taper-roller bearings.

5. A baling press as claimed in any of claims 1 to 4, wherein for a press capacity of 20 tons and a press area of approximately 80 cms x 120 cms, the electric driving power of each driving motor amounts to approximately 2.2 kW.

6. A baling press as claimed in claim 1, wherein a braking device locking the motor spindle when at rest, is coupled to the driving spindle of the driving motor.

7. A baling press as claimed in claim 6, wherein the braking device is an electromagnetic brake.

8. A baling press as claimed in claim 1 and 6 or 7, wherein the press spindle has a double lead screw thread or rather a thread not having a self-locking action.

9. A baling press as claimed in claim 6,7 or 8, wherein the actuating switch of the braking device at the same time forms the motor end of travel switch for deactivation of the press stroke at the terminal position.

10. A baling press as claimed in claim 6,7 or 8, wherein the actuating switch of the braking device is connected to the overload safety switch.

11. A baling press according to claim 7, wherein the electromagnetic brake comprises a springloaded thrust plate connected co-rotatorily to the driving spindle which, in its off position, bears under spring loading on the brake plate.

12. A baling press as claimed in claim 1, wherein a transmission gear for increasing the speed of revolution of the driving spindle is situated between the braking device and the driving spindle.

13. A baling press as claimed in claim 6, wherein the braking device is a mechanically acting brake.

14. A baling press substantially as hereinbefore described with reference to the accompanying drawings.