GB2305140A

GB2305140A - Vice for a band saw

Info

Publication number: GB2305140A
Application number: GB9518743A
Authority: GB
Inventors: Jack Elliott
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-09-13
Filing date: 1995-09-13
Publication date: 1997-04-02
Anticipated expiration: 2015-09-13
Also published as: GB9518743D0; GB2305140B

Abstract

A vice for holding a workpiece while being sawn in a band saw or the like, comprises two jaws 40, 41 axially displaceable in relation to one another for gripping the workpiece therebetween. Each jaw includes a gripping surface divided into first and second portions 51, 52, 53, 54 by a slot 55, 56 for allowing passage of the saw blade therethrough. The first and second portions are connected to one another by a base portion 50 which lies below the maximum extent of downward travel of the saw. The base portions of each jaw are coupled to an axial drive mechanism to drive at least one of the jaws against the other. The vice enables gripping of both parts of a workpiece to be separated from one another during the sawing operation, while providing a stable bed for the two halves which does not interfere with the passage of saw entirely through the workpiece. The entire vice may be tilted up or down (Fig. 6, not shown).

Description

VICE FOR A BAND SAW The present invention relates to vices, and in particular to vices which may be used for holding a workpiece during a sawing operation.

The problems associated with securely holding workpieces while carrying out sawing operations are well known. Typically a vice is employed to hold one end of the workpiece in a suitable position and orientation for a saw blade to pass right through the workpiece in the desired position, leaving the free, or unclamped, end of the workpiece to fall off the main body once the saw blade has passed right through the workpiece.

In electrically powered saws, such as band saws, the vice and a work bench area are typically integrally formed with the saw mechanism such that the saw blade passes down the side of a workpiece vice. A typical arrangement is shown schematically in figure 1. A work surface or saw bed 10 supports a vice 12 with two jaws which are axially moveable in relation to one another in known manner. The saw is positioned such that the blade 20 passes down the sides of the vice jaws 15,16, typically 1-2 cm distant from the vice jaws.

In order that the saw blade may travel past the full depth of the vice jaws, it is common practice to include a recess 25 in the saw bed 10, into which the saw blade may travel in the downward direction. This is particularly useful so that a workpiece may be held flat against the saw bed 10, while being gripped by the vice jaws, during the cutting operation. This enables the workpiece to be held more securely: the downward force of the saw blade on the workpiece is resisted by the saw bed, and not through shear forces on the vice jaws. This is particularly important for fragile or soft workpieces, eg. pipes which may be deformed by excessive vice pressure. In addition, placing the workpiece on the saw bed allows for accurate registration of the workpiece to a plane orthogonal to the plane of the saw blade.

In order to prevent damage to the saw bed (ie. the bottom of the recess 25) or saw blade, it is customary to include a mechanical stop (not shown) in the saw blade guide mechanism (also not shown) to limit the travel of the saw blade in the downward direction, and thereby prevent collision of the saw blade with the bottom of the recess 25.

The arrangement shown in figure 1 has a number of disadvantages.

For example, particularly small workpieces cannot be reliably or securely held in the vice where the cutting line in the workpiece is only a few centimetres or a few millimetres distant from the body of the workpiece which must be gripped by the vice jaws. In addition, the portion of the workpiece which become detached during the cutting operation is free to fall away, possibly at dangerously high speed where a fast saw blade is in operation, unless separately restrained by either the operator, or a further, separate, clamp mechanism. Such restraint by the operator can be dangerous and use of a separate clamp mechanism is time consuming and inconvenient.

It would be advantageous to be able to provide a single vice which can simultaneously hold both portions of a workpiece to be severed from one another, while allowing passage of the saw blade completely through the workpiece.

It is an object of the present invention to provide a vice suitable for use in conjunction with, for example, with a band saw, which simultaneously grips both portions of a workpiece to be severed from one another, while allowing passage of the saw blade completely through the workpiece.

It is a further object of the invention to provide such a vice which is capable of applying substantially similar pressure to both portions of the workpiece to be severed from one another during the sawing operation.

It is a further object of the invention to provide a saw bed on which the workpiece may be placed during the sawing operation.

In accordance with one aspect, the present invention provides a vice comprising two jaws axially displaceable in relation to one another for gripping a workpiece therebetween, each jaw including a gripping surface divided into first and second portions by a slot for allowing passage of a saw blade therethrough, the first and second portions connected to one another by a base portion, the base portions of each jaw being coupled to an axial drive mechanism.

In accordance with another aspect, the present invention provides a vice having opposing jaws adapted to grip a workpiece on opposing sides of the workpiece and on both sides of a cutting line on the workpiece, the vice being adapted to allow passage of a saw blade entirely through the workpiece on the cutting line in a plane which is transverse to a gripping surface of at least one jaw of the vice. The vice may be further adapted to support the workpiece on a plane intersecting the two planes defined by the gripping surfaces of the opposing jaws.

The present invention will now be described by way of example and with reference to the accompanying drawings in which: Figure 1 shows a schematic diagram of a prior art arrangement of band saw vice; Figure 2 shows a perspective view (from the right, rear corner) of a vice according to the present invention; Figure 3 shows a front view of the vice of figure 2; Figure 4 shows a back view of the vice of figure 2; Figure 5 shows a plan view of the vice of figure 2; Figure 6 shows a right side view of the vice of figure 2, also illustrating a pivoting action of the vice on a support block.

With reference to figure 2 a presently preferred embodiment of the present invention is shown from the rear, right-hand corner in order to provide optimum view of the various constituent parts. Corresponding front, back, plan and right side views are shown in figures 3 to 6 respectively.

A vice 30 comprises a support fame 32 which includes guide rails 33,34 and end stops 35,36 for guiding and constraining movement of a first jaw 40 along an axial direction (shown by arrow A) defined by the guide rails 33,34. In the embodiment shown, a second jaw 41 is fixed to, or integrally formed with, the end stop 36 to provide a non-moving jaw, although it will be understood that this jaw could also be moveable along the same axis as the first jaw in known manner.

An axial drive mechanism is provided to drive the moving jaw 40 in a manner well known in the art. A central shaft 45 passes through the support frame 32 from rear end stop 36, through the moving jaw 40, to a handle collar 46 at the front of the vice 30. The drive shaft 45 is retained in position by lock nuts 47 and handle collar 46. The action of this drive mechanism is, so far, entirely conventional in providing a driving action for moving jaw 40 within the support frame 32.

As suggested above, the fixed jaw 41 is preferably an integral, upstanding part of the end stop 36. The moving jaw 40 comprises a base portion 50 through which the central shaft 45 passes for the purpose of driving the jaw 40, and a gripping surface divided into two portions 51,52 which are separated by a slot 55 which passes through the entire thickness of the jaw (ie. front to back). The fixed jaw 41 also includes a "base portion" which, in the embodiment illustrated, essentially corresponds to the end stop 36.The fixed jaw also includes a gripping surface which is divided into two portions 53,54 which are separated by a slot 56 which passes through the entire thickness of the jaw. Ft will be understood that if the fixed jaw 41 were replaced by a second moving jaw, the base portion may reside between the guide rails 33,34 similar to the moving jaw 40, and may be of the type which allows it to be locked into a number of axial positions independent of the jaw 40. Such are arrangements are well known, and will not be discussed further.) The slots 55,56 may be located at any lateral position in the jaws 40,41, ie. to the left or right of the central shaft 45, or even to the left or right of the side rails 33,34 as viewed from the front (figure 3) or back (figure 4) of the vice 30. If the slots 55,56 are positioned laterally outside the side rails 33,34, then the base portion 50 must extend over the relevant side rail so that the depth of the slot is not sufficient to reach the top surface of the side rail.

However, it is preferable for the slots 55,56 to be laterally positioned between the guide rails, and still further it is preferable to laterally position the slots substantially above the central shaft 45, as shown in the figures. This ensures that there is a well-balanced gripping pressure on a workpiece positioned between the jaws 40,41 and across the slots 55,56, and little tendency for the jaws to distort to a non-parallel configuration.

In use, a workpiece is introduced between the vice jaws 40,41 such that the intending cutting line on the workpiece is situated co-linear with the slots 55,56. The workpiece is therefore gripped on one side of the cutting line by corresponding jaw portions 51 and 53, and on the other side of the cutting line by corresponding jaw portions 52 and 54. A bandsaw blade or the like is then introduced in a downward direction into the slots 55,56 to sever the workpiece into its two parts.

As indicated earlier in this specification, it is highly desirable when using a vice in conjunction with a saw, to provide a saw bed on which a workpiece being sawn may rest during the cutting operation. In the preferred embodiment, the present invention provides two moveable saw bed members 60,61 which are pivotable about a saw bed member shaft 64 which is attached to the outer side of the side rail 33. Preferably, the saw bed members are also slidable along the shaft 64 in the axial direction.

The saw bed members may thereby be introduced into the space between the jaws 40,41 (as shown) at axially appropriate positions according to the thickness of the workpiece being gripped between the jaws. Although only two saw bed members are shown in the preferred embodiment of figure 2, it will be understood that any appropriate number can be used.

When not in use, the saw bed members 60,61 may be rotated about shaft 64 (in a clockwise direction as viewed from the front) to clear them from the path of the vice jaw 40.

Preferably, each of the saw bed members 60,61 incorporates a slot 65 which lies in alignment with the jaw slots 55,56 when the saw bed member 60,61 is in position between the jaws 40,41. In use, the saw bed members 60,61 are swivelled about shaft 64 to introduce them into the space between the jaws 40,41 at an appropriate distance apart to support front and back ends of the workpiece. The vice jaws are then tightened sufficiently to retain the workpiece in position laterally. The saw blade is introduced into the slots 55,56, travels down through the workpiece, passing through the workpiece and into slots 65.

In the preferred embodiment, the saw blade is prevented from overtravel causing collision with either the bottom of jaw slots 55,56, or saw bed member slots 65 by way of a suitable stop platform 70. Stop platform 70 comprises upper portions 71,72 against which a corresponding part of the saw blade housing (not shown) will collide at a prescribed depth of saw blade cut. Recess 73 is provided to accommodate the saw blade.

As shown in figure 2, the central shaft 45 terminates at the front of the vice 30 with a handle collar 46. Coupled to the collar 46 is a handle 49. In this preferred embodiment, collision of the saw blade with the handle 49 is prevented if the handle is left at a position below the level of the lowest position of the saw blade. To achieve this, the handle may be provided with a suitable disengagement mechanism, exemplified in figure 6.

With reference to figure 6, the handle collar 46 is axially slidable and rotatable on the central shaft 45 and has two teeth 80,81 which engage with slots on a fixed collar 83 on the shaft 45. When the handle collar 46 is pressed inwards toward the fixed collar, it is in driving engagement with the shaft 45 and the handle 49 can be used to adjust the vice jaw 40 position. When the handle collar 46 is pulled outwards from the fixed collar 83, the teeth 80,81 are disengaged therefrom and the handle becomes free-running on the shaft 45. Thus, wherever the moving jaw 40 is positioned, the handle 49 may always be returned to a low position. A similar effect may be achieved with a reversible ratchet arrangement or other mechanism well known in the art.

With reference to figure 1 and to figure 2, the vice 30 is preferably provided with a support block 90 for attaching the vice to the conventional band saw vice arrangement shown in figure 1. Support block 90 is introduced into the jaws of vice 12, with the vice 30 extending out to the right of the vice 12, aligning the slots 55,56 with the line of travel of the blade 20.

Many band saws provide a saw blade housing which descends through an arc by way of a pivot at the back of the machine. Thus, it will be understood that the angle at which the saw blade arrives at the saw bed members 60,61 of the vice 30 will not necessarily be exactly horizontal, particularly if the saw bed members 60,61 are higher than the saw bed 10 of the conventional band saw of figure 1. Thus, the vice 30 may be coupled to the support block 90 using a pivot mount (not shown) enabling the entire vice 30 to tilt up or down front-to-back as best shown in figure 6. This enables very precise registration of the saw bed members 60,61 to the bottom of the travel of the saw blade.

Alternatively, the vice 30 may be provided with flat bed mountings such as lugs 95 (figure 2).

It will be understood that the vice of the present invention may be incorporated into a conventional band- or other saw bed.

Typically, saws produce a considerable quantity of swarf or dust directly beneath them. In particular in band saws, this tends to cascade out of the back of the vice. Where the blade is directly over the central shaft 45, this can cause clogging of the screw thread. A protective cover 98 (only shown on figures 4 and 5) may therefore be provided to the shaft and lock nuts 47 at the back of the vice 30, and also to the handle collar 46 / fixed collar 83 interface at the front end of the vice.

It will be understood that because the vice jaw portions 51,52 and 53,54 are accurately and rigidly registered to one another in the lateral directions, very precise positioning of the saw blade relative to the slots 55,56 is possible. Thus, the slots can be made barely wider than the blade width resulting in excellent gripping properties and precise positioning of even very small workpieces or offcuts of larger workpieces. The slots 55,56 are preferably of a width between one and ten times the saw blade width, and more preferably between one and three times the saw blade width.

Claims

1. A vice comprising two jaws axially displaceable in relation to one another for gripping a workpiece therebetween, each jaw including a gripping surface divided into first and second portions by a slot for allowing passage of a saw blade therethrough, the first and second portions connected to one another by a base portion, the base portions of each jaw being coupled to an axial drive mechanism.

2. A vice according to claim 1 further including a number of axially moveable saw bed members adapted to be interposed between the two jaws to provide a saw bed between the gripping surfaces of both jaws.

3. A vice according to claim 2 in which the saw bed includes a bed slot for passage of a saw blade therethrough, substantially in alignment with the slots in the jaws.

4. A vice according to claim 2 or claim 3 in which the axially moveable saw bed members are pivotally coupled to a bed member shaft substantially parallel to the vice axis.

5. A vice according to claim 1 coupled to a lateral support block.

6. A vice according to claim 5 in which the vice is pivotable with respect to the lateral support block about an axis substantially orthogonal to the vice axis.

7. A vice according to claim 1 in which the axial drive mechanism is a screw drive member passing below the gripping surfaces of the jaws.

8. A vice according to claim 7 in which the screw drive member includes a drive handle having a first state in which it is coupled to rotatably drive the screw drive member and a second state in which it is free running to rotate about the screw drive member.

9. A vice according to claim 8 in which the drive handle is placed in the first state from the second state by axial displacement of the handle to engage the handle with a clutch member.

10. A vice according to claim 8 in which the drive handle is coupled to the screw drive member by way of a reversible ratchet mechanism.

11. A vice according to claim 7 in which the screw drive member is positioned substantially in line with and below the slots.

12. A vice according to claim 11 further including a swarf protection cover over an end of the screw drive member.

13. A vice having opposing jaws adapted to grip a workpiece on opposing sides of the workpiece and on both sides of a cutting line on the workpiece, the vice being adapted to allow passage of a saw blade entirely through the workpiece on the cutting line in a plane which is transverse to a gripping surface of at least one jaw of the vice.

14. A vice according to claim 13 further adapted to support the workpiece on a plane intersecting the two planes defined by the gripping surfaces of the opposing jaws.

15. A saw incorporating a vice according to claim 1, claim 2, or claim 3.

16. A band saw incorporating a vice according to claim 1, claim 2 or claim 3.

17. A saw according to claim 15 or claim 16 further including a mechanical stop adapted to prevent the saw blade reaching the bottoms of the slots.

18. A saw according to claim 15 or claim 16 in which the slots are dimensioned to have a width between one and ten times the width of the saw blade.

19. A saw according to claim 18 in which the slots are dimensioned to have a width between one and three times the width of the saw blade.

20. A vice substantially as described herein with reference to the accompanying figures 2 to 6.