GB2214865A - Band saw for dividing up animal carcases - Google Patents

Abstract

A band saw (10) for dividing up animal carcases has two rollers (13 and 14) on which a saw band (15) is guided. The roller (14) can be displaced to change the spacing of its axis from the axis of the other roller (13). For this purpose, the roller (14) is guided for longitudinal movement in a slide and the slide can be displaced by a tensioning device (17) which is limited by its design, in terms of its total travel, so as to permit only a structurally predetermined maximum tension of the saw belt (15) to be obtained regardless of the adjustment skills of the operator. Risk of extensive high tension can therefore be avoided. The tensioning device (17) comprises a tensioning member (22) moved to its tensioning position by movement of a cover (12). In Fig 4 (not shown), the tensioning member (22a) comprises a cam plate. Setting guides (16) for the interlaced guidance of a cutting pass (15a) of the saw band, each comprise two guide parts (18, 19 Fig 3) displaceable relative to one another upon opening and closing of a cover (12). <IMAGE>

Description

BAND SAW FOR DIVIDING UP ANIMAL CARCASES The invention relates to a band saw for dividing up animal carcases.

Such a saw may have a substantially closed housing with a hinged cover, two rollers rotatably mounted in the housing and spaced apart from each other, a saw band revolving around the rollers and two setting guides for the interlaced guidance of the cutting pass of the saw band, with at least one of the rollers being displaceable by means of a tensioning device in order to tension the saw band by varying the spacing of its axis from the axis of the other roller.

Band saws of this kind have been previously proposed and it has been found that in such band saws, and particularly by virtue of their partially interlaced guidance arrangements, the saw band wears out or breaks relatively quickly.

For this reason, the saw band frequently has to be changed, every endeavour being taken to minimise the time required to change the saw band in order to cut to a minimum the interruption in working which the task entails.

When a saw band is changed, it is necessary firstly to shut down the band saw, then open up the cover, relieve the tension on the saw band by reducing the spacing between the axes of the two rollers and cancel out the set of the saw band. When the worn out or broken saw band has been removed, a new saw band can be fitted, tensioned and set, after which the cover can be closed.

Where previously proposed band saws are concerned, the saw band is tensioned via a threaded spindle by means of which the adjustable roller can be moved in relation to the other roller.

In practice it is quite frequent for excessive tension to be created in the saw band and this can lead to destruction of the saw band even during the actual tensioning process.

In any case, excessive tension in the saw band is unfavourable, since increased band tension leads to premature destruction of the saw band.

According to the invention there is provided a band saw for dividing up animal carcases, comprising a substantially closed housing with a hinged cover, two rollers rotatably mounted in the housing and spaced apart from each other, a saw band movable around the rollers, two setting guides for the interlaced guidance of a cutting pass of the saw band, and a tensioning device to displace at least one of the rollers to tension the saw band by varying the spacing between the axes of the two rollers, the total displacement effected by the tensioning device being limited by a tensioning member movable between a slack position and a clamped position.

In such a band saw manual operations required when changing a saw band can be carried out more easily and reliably, particularly where the tension of the saw band is concerned.

Such an improvement in the tensioning device can give the advantage that excessive tension in the saw band is avoided since an operator is only capable of utilising the limited total travel of the tensioning member. This total travel is structurally so designed that optimum tension of the saw band is achieved by this total travel.

The invention is diagrammatically illustrated by way of example in the accompanying drawings, in which: Figure 1 is a diagrammatic view of a band saw according to one embodiment of the invention for dividing up animal carcases, with a cover open; Figure 2 is an enlarged partial view of the band saw of Figure 1 showing a roller and a setting guide; Figure 3 is a partial view in the direction of arrow III in Figure 2; and Figure 4 is a partial view of a band saw according to a further embodiment of the invention, shown with a cover open.

A band saw 10 shown diagrammatically in Figure 1, for dividing up animal carcases, comprises a substantially closed housing 11, a cover 12 which is hinged onto the housing 11, two rollers 13 and 14 rotatably mounted in the housing and at a spacing from each other, a saw band 15 passing around the rollers 13 and 14, two setting guides 16 for the interlaced guidance of a cutting pass 15a of the saw band 15 and a tensioning device 17 whereby the distance between the axes of the two rollers 13 and 14 can be varied and the saw band 15 thus tensioned.

Referring to Figures 2 and 3, the setting guides 16 in each case comprise two guide parts 18 and 19 which extend perpendicular to the direction of movement of the cutting pass 15a of the saw band 15. The two guide parts 18 and 19 are coupled to each other in constrained fashion and are displaceable in opposition to each other. For reasons of clarity, a concrete illustration of the positive coupling between the two guide parts 18 and 19 has been waived in Figures 2 and 3 but the double-headed arrows A and B shown in Figure 3 symbolically represent the positive displacement of the two guide parts 18 and 19.

As Figure 3 shows the guide part 18 is constructed as a rack which meshes with a hinge pin 20 of the cover 12, the hinge pin 20 being constructed at least partially as a pinion.

Upon opening or closing of the cover 12, the hinge pin 20 which is connected rigidly to the cover 12 rotates accordingly. This rotary movement is transmitted to the guide part 18 which is constructed as a rack and converted into a longitudinal displacement of the guide part 18. By virtue of the constrained coupling to the guide part 19, the guide part 19 is then accordingly displaced in the opposite direction.

As Figure 2 further shows, the saw band 15 is, in the region of its cutting pass 15a, set into the plane of the rollers 13 or 14 when the cover 12 is closed, only a tooth free portion of the saw band 15 being engaged between the two guide parts 18 and 19. The position of the guide parts 18 and 19 when the saw band 15 is set is indicated by dash-dotted lines in Figure 3. Solid lines indicate the position of the guide parts 18 and 19 which occurs when the cover 12 is open, in which position, the saw band 15 can easily be removed from the setting guides 16.

Figure 2 shows that the tensioning device 17 for tensioning the saw band 15 comprises an actuating assembly 21 and a tensioning member 22. The roller 14, together with a mounting 23 therefor, is displaceable by means of the tensioning member 22 in a slide 24 in order to vary the spacing of the axis of the roller 14 from the axis of the other roller 13.

The actuating assembly 21 can take the form of a rack and be driven by the hinge pin 20 which is at least partially constructed as a pinion.

The tensioning member 22 is produced from two parts which are displaceable telescopically in relation to each other and is provided with a compensating spring 25, the compensating spring 25 on the one hand bridging fitting tolerances and on the other limiting the maximum tension of the saw band 15.

Since the movement of the tensioning member is derived from the movement of the actuating assembly 21 which is constructed as a rack, the total travel effected by the tensioning device 17 is limited by the possible extreme positions of the tensioning member 22, that is to say when the cover 12 is closed the tensioning member 22 assumes its tensioning position which corresponds to the maximum tension on the saw band 15. When the cover 12 is open, the tensioning member 22 assumes a slack setting, which means that in this position the two rollers 13 and 14 move more closely together so that there is no longer any tension at all in the saw band 15 and it can easily be removed from the rollers 13 and 14. It is then simple to fit a new saw band 15 on the rollers 13 and 14 and then to obtain optimum tension by closing the cover 12.

Since the total travel effected by the tensioning device is virtually predetermined, there is no possibility of the saw band becoming excessively tensioned due to error on the part of operating personnel.

In the embodiment shown in Figure 4, the roller 14 is again mounted for displacement in a slide 24 so that the distance of its axis from the axis of the second roller 13, not shown in Figure 4, can be varied. A tensioning member 22a constructed as a cam plate, cooperates with a push rod 28 which carries a cam follower roller 27 which follows a guide cam 29 extending eccentrically of the centre of the cam plate. The total travel effected by the tensioning device 17 is limited by the pitch of the guide cam 29.

The tensioning member 22a which is constructed as a cam plate can, in the embodiment shown in Figure 4, be actuated either independently of the cover 12 by means of a suitable tool or by movement of the cover 12 and its hinge pin 18. There is connected to the hinge pin 18 an actuating cord 30, the other end of which is connected to the tensioning member 22a.

When the cover 12 is closed, the actuating cord 30 is wound around the hinge pin 18, simultaneously rotating the cam plate so that the roller 14 is displaced leftwardly from the position shown in the drawing in Figure II and is thus clamped.

The two embodiments illustrated while different in design both limit the total travel effected by the tensioning device 17, so that the tension of the saw band 15 is not dependent upon the skill of the operator.

Claims (10)

1. A band saw for dividing up animal carcases, comprising a substantially closed housing with a hinged cover, two rollers rotatably mounted in the housing and spaced apart from each other, a saw band movable around the rollers, two setting guides for the interlaced guidance of a cutting pass of the saw band, and a tensioning device to displace at least one of the rollers to tension the saw band by varying the spacing between the axes of the two rollers, the total displacement effected by the tensioning device being limited by a tensioning member movable between a slack position and a clamped position.

2. A band saw according to claim 1, in which the tensioning member is a tensioning lever movable within predetermined limits by means of an actuating assembly.

3. A band saw according to claim 2, in which the actuating assembly is a rack and pinion with the pinion formed by a hinge pin of the cover.

4. A band saw according to any one of the preceding claims, in which the tensioning member comprises two telescopically reciprocally displaceable parts biased to extend by a compensating spring.

5. A band saw according to claim 1, in which the tensioning member comprises a rotatable cam plate including a tensioning cam extending eccentrically of the axis of rotation of the cam plate and cooperating with a push rod provided with a cam follower roller, which push rod can displace said at least one of the rollers.

6. A band saw according to claim 5, in which one end of an actuating cord is connected to the cam plate and the other end is attached to a hinge pin of the cover.

7. A band saw according to any one of the preceding claims, in which each of the setting guides comprises two guide parts extending perpendicular to the direction of movement of a cutting pass of the saw band and effective, when the cover is closed, to hold a tooth-free portion of the saw band between them substantially in the plane of the rollers, the two guide parts being displaceable in opposition to each other in a constrained coupled arrangement.

8. A band saw according to claim 7, in which one of the guide parts can be driven by means of a hinge pin rigidly connected to the cover.

9. A band saw according to claim 8, in which the driven guide part is constructed as a rack and the driving hinge pin is at least partly constructed as a pinion.

10. A band saw for dividing up animal carcases substantially as hereinbefore described and illustrated with reference to the accompanying drawings.