GB2421214A

GB2421214A - Jigsaw with adjustable depth

Info

Publication number: GB2421214A
Application number: GB0427833A
Authority: GB
Inventors: John Stewart
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-12-20
Filing date: 2004-12-20
Publication date: 2006-06-21
Also published as: GB0427833D0

Abstract

Means are provided which allow the depth of cut of a jig saw to be varied according to the nature of the workpiece. A typical means provides the ability to vary the position of the foot plate of the jig saw in relation to the position of the means that secures the cutting blade. The means may be supplied as an attachment to a conventional jig saw or as an integral part of a jig saw.

Description

IMPROVEMENTS IN OR RELATING TO JIG SAWS The present invention relates to improvements in or relating to jig saws. Jig saws are used to cut fine patterns in a workpiece such as lines, circles, curves, and the like. The relatively thin blade of the jig saw, as opposed, for example, to the relatively large blade of a circular saw, make it ideal for cutting operations which still need to be precise but are not necessarily in a straight line Portable jig saws typically include a housing containing an electric motor for reciprocating a saw blade which extends perpendicularly from the bottom of the housing and having cutting teeth that face toward the front of the housing. Typically, a footplate is disposed at the bottom of the housing and provides a generally flat surface to support and guide the jig saw during cutting. The flat bottom of the footplate is placed on, and slides over, a workpiece being cut so that the operator can guide the blade to obtain the desired cut.The footplate has a slot through which the saw blade extends to engage the workpiece and during cutting the blade reciprocates at this position while the jig saw is moved in a generally forward direction. Some jig saws can also be used to form bevel-edge cuts, which are cuts formed at an angle with respect to the plane of the bottom of the footplate. Such jig saws include a mechanism for adjusting and locking the position of the footplate with respect to the housing and the saw blade. In use, the blade maintains its perpendicular orientation with respect to the housing, but is at a different angular orientation with respect to the plane of the bottom of the footplate. Thus, since the planar surface of the footplate remains in contact with the planar surface of the workpiece, when the saw blade is maintained at an angle with respect to the footplate, the resulting cutting operation will also be at an angle. Jig saws are used in a variety of applications generally for the cutting and shaping of thin materials such as wood flooring, thin metal and the like. The operating principle of the jig saw being that a cutting blade oscillates in a vertical plane and is brought against the material to be cut which lies in a substantially horizontal plane so that the cut is effected by the oscillating motion of the blade. As described jig saws are also frequently provided with a footplate that rides on the surface of the material that is being cut. The plate acts as a guide to control the direction taken by the cutting blade as it performs the cutting action and also to maintain the cutting blade in the desired orientation in relation to the material being cut. The foot plate can also act as a safety device in that it surrounds the oscillating cutting blade. A jig saw needs to be versatile and have the capability of performing different tasks and in particular to cut different types of materials and different thicknesses of material. The versatility of a jig saw has hitherto been controlled by varying the speed of oscillation of the cutting blade, the length of the cutting blade and the nature of the cutting blade such as the length of the blade and the density and pitch of the teeth. These systems however require the use of many different cutting blades and involve time consuming changing of blades. We have now found that the flexibility of a jig saw may be significantly increased whereby the depth of the stroke of the cutting blade through the workpiece can be adjusted and in particular if the jig saw is provided with means to vary the distance between the blade holder and the surface of the footplate that is to be in contact with the material to be cut. Accordingly the present invention provides a jig saw comprising a housing including means for securing a cutting blade and a footplate wherein means are provided whereby the depth of the stroke of the cutting blade through the workpiece can be adjusted and in particular for varying the distance between the means for securing the blade and the surface of the footplate designed to be in contact with the material that is being cut. The present invention therefore increases the flexibility of the jig saw in that the depth of the stroke of the cutting blade through the workpiece may be adjusted according to the particular cutting task that is required. The depth of the stroke of the cutting blade may be accomplished by varying the distance between the means for securing the blade and the surface of the foot plate designed to be in contact with the material that is being cut. The means may be a separate attachment that can be used with an existing jig saw. Alternatively it may be an integral part of the jig saw. One benefit of the present invention is that it provides a jig saw which could be used to cut through various materials yet without penetrating beyond the thickness of the material itself. For example, this is helpful when cutting through studwork, flooring, or other surfaces behind which pipes, cables, or other objects may be located. At present, flooring is typically ripped through by setting the depth of a circular saw. However, this method does not result in a square cut and may also damage the blade if nails or screws are struck This, them, requires the blade to be discarded which represents an additional cost when performing this type of work. The jig saw depth setting provided by the present invention would correct these shortcoming.The depth setting device could either be affixed to an existing jig saw as an aftermarket kit or incorporated into new jig saws at the point of manufacture. The kit version could use snap-on interlocking plates of various thickness that would fit onto existing jig saw footplates. The ability to set the depth of a jig saw would serve as a functional aid for use by both professional tradesmen and DIY enthusiasts when working with jig saws. The position of the blade could be set to correspond with the material being cut, thereby reducing the risk that objects on the other side might be struck. This, of course, could result in a costly and inconvenient situation, if say a jig saw blade accidentally severs a water pipe or electrical cable. In the latter instance, this could also pose a safety hazard as well. A further advantage of the present invention is that the jig saw could be set such that only a portion of the jig saw blade would be used and, when this section becomes dull, the setting could be adjusted so that the unused portion of the blade is then used. This would effectively double the useful life of a typical jig saw blade. The primary benefits of the Jig saw depth setting offers convenience and increased work efficiency. The convenience benefit would be realised through the way in which this device would enable a professional tradesman or DIY enthusiast to perform construction, remodelling and renovation work that involves cutting through walls, floors or other surfaces using a jig saw in a quicker and easier manner than would typically be the case when using only a standard jig saw fitted with a blade of conventional length. For anyone who has experienced the inconvenience of executing this type of work in a precise manner using only a conventional jig saw and blade, the jig saw dept setting should be a welcomed addition to their collection of tools and equipment. The present invention is illustrated by reference to the accompanying drawings. Figure 1, shows a conventional jig saw (1) that includes a housing (2), a flat elongated jig saw blade (3), and a footplate (4). The blade (4) is secured near the bottom of the front part of the housing (2). The blade (4) has cutting teeth (5) along its forward edge facing in the direction forward of the jig saw (1). The footplate (4) has an underside (6) that is generally planar, smooth and frictionless so as to guide and support the jig saw (1) upon the planar surface of a workpiece (not shown) during a cutting operation. The footplate (4) has a generally U-shaped opening (7) through which the blade (4) extends in order to engage the workpiece. During a cutting operation, the jig saw (1) slides in a generally forward direction thereby engaging the cutting teeth (5) of the reciprocating blade (4) into the workpiece to make the desired cut. Figure 2 shows a jig saw depth setting device according to the present invention which may be attached to a conventional jig saw such as that illustrated in Figure 1. The jig saw setting device comprising a jig saw foot support (8) the upper surface (9) of which is recessed to allow it to be slideably and removeably attached to the footplate (4) of the jig saw. The support is provided with a U-shaped recess (10) at one end to provide a safety area for the reciprocating blade. The setting device also has a lower base plate (11) connected to the upper surface plate (9) by pivots (12) and (14) which can be operated by the height adjusting screw (13) to increase or decrease the distance between the upper surface (9) and the lower base plate (11). In this way the distance between the means for securing the cutting blade and the lower base plate (11) can be varied to vary the cutting stroke of the blade according to the cut required.

Claims

1. A means to increase the flexibility of the jig saw in that the dept of the stroke of the cutting blade through the workpiece may be adjusted according to the particular cutting task that is required.

2. A means according to Claim 1 in which the depth of the stroke is adjusted by varying the distance between the means for securing the blade and the surface of the foot plate designed to be in contact with the material that is being cut.

3. A means according to Claim 1 or Claim 2 in which the means is a separate attachment that can be used with an existing jig saw.

4. A means according to Claim 1 or Claim 2 which is an integral part of the jig saw.

5. A means according to any of the preceding Claims comprising a kit version of snap-on interlocking plates of various thickness that fit onto existing jig saw foot plates.

6. A means according to any of the preceding Claims whereby the position of the blade could be set to correspond with the thickness of the material being cut.

7. A jig saw provided with means to adjust the depth of the stroke of the cutting blade through the workpiece may be adjusted according to the particular cutting task that is required.

8. A jig saw according to Claim 7 in which comprises a means whereby the depth of the stroke is adjusted by varying the distance between the means for securing the blade and the surface of the foot plate designed to be in contact with the material that is being cut.

9. A jig saw according to Claim 8 or Claim 9 in which the means is a separate attachment that can be used with an existing jig saw.

10. A jig saw according to Claim 8 or Claim 9 in which the means is an integral part of the jig saw.

11. A jig saw according to any of Claims 7 to 10 in which the means comprises a kit version of snap-on interlocking plates of various thickness that fit onto existing jig saw foot plates.

12. A jig saw according to any of Claims 7 to 12 whereby the position of the blade could be set to correspond with the thickness of the material being cut.