Abstract:
A preferred embodiment of the present invention comprises a foot assembly for a power hand tool such as a jigsaw that has an angularly adjustable support foot with a generally flat bottom, at least two spaced apart supports connected to the support foot, an elongated rod extends through apertures in the supports in a configuration that permits limited sliding movement and the angular adjusting movement of the support foot relative to the hand tool, a retainer member associated with the hand tool that selectively engages one of the supports to lock the support foot at predetermined angular positions, and a spring biases the retainer member toward engagement with the support. A second embodiment includes a removable transparent plate that attaches to the support foot and has a faux laser line for a cutting aid.

Description:
FIELD OF THE INVENTION 
   The present invention generally relates to power hand tools of the type which have foot assemblies. 
   BACKGROUND OF THE INVENTION 
   Electric power hand tools such as portable electric jigsaws are well known in the art and have been the subject of continued research and development that has resulted in commercial products that are more convenient to operate and enable users to produce superior results. Generally, they include an AC, DC or universal electric motor contained in a housing and a tool such as a saw blade operatively driven by the shaft. In the case of a jigsaw as well as other cutting tools, a foot assembly is provided which is connected to the base of the tool housing and generally comprises a flat bottom surface platform for engaging a work piece during operation. 
   Most jigsaws and some other power tools have a foot assembly that can be tilted relative to the tool housing so that cuts can be made at an angle to achieve a beveled cut. While foot assemblies that can be tilted have been known in the art for decades, many of the early and some of the recent mechanisms for adjusting and/or locking the foot at a desired angle to the tool housing are often cumbersome to use. A screwdriver, wrench, or the like is often required to tighten one or more threaded locking members such as bolts, which can be time consuming and even difficult if one does not have the appropriately sized and configured tool at hand. Sawdust and other debris created by the jigsaw can also combine with saw lubricants to foul the threaded locking member. 
   Some hand tools have an onboard locking lever to lock the foot in place at a desired orientation to the tool housing, which solves the problem of having the correct tool at hand, but often such locking levers were relatively costly to manufacture and cumbersome to install and adjust. Some hand operating levers may not conveniently provide the requisite holding strength, which when coupled with the substantial vibration developed during operation of a jigsaw can result in an undesirable change in the orientation angle of the foot. 
   Other solutions to movement of the foot have included foot assemblies that combine an onboard hand operable locking lever in combination with a plurality of guide openings that are selectively engageable with a locking extension which minimizes the possibility of the orientation angle changing during use. 
   SUMMARY OF THE INVENTION 
   A preferred embodiment of the present invention is a foot assembly for a power hand tool such as a jigsaw that has an angularly adjustable support foot with a generally flat bottom portion, at least two spaced apart supports connected to the support foot, with each support having a main aperture, an elongated rod extending through the main apertures of the supports in a configuration permitting limited sliding movement and the angular adjusting movement of the support foot relative to the hand tool, a retainer member associated with the hand tool for selectively engaging at least one of the supports to lock the support foot at predetermined angular positions, and a spring for urging the retainer member toward engagement with the at least one support. 
   A second embodiment includes a removable transparent plate that attaches to the support foot and has a faux laser line for a cutting aid. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a right side view of a jigsaw having the preferred embodiment of the foot assembly of the present invention; 
       FIG. 2  is a front plan view of the jigsaw shown in  FIG. 1   
       FIG. 3  is a right front perspective view of the jigsaw shown in  FIG. 1  with portions removed, and illustrating the foot assembly locked in the 0 degree position; 
       FIG. 4  is a right front perspective view of the jigsaw shown in  FIG. 1  with portions removed, and illustrating the foot assembly in the 0 degree position, and in an unlocked position; 
       FIG. 5  is a right front perspective view of the jigsaw shown in  FIG. 1  with portions removed, and illustrating the foot assembly in a 45 degree position, and in an unlocked position; 
       FIG. 6  is a right front perspective view of the jigsaw shown in  FIG. 1  with portions removed, and illustrating the foot assembly in a 45 degree position, and in an locked position; 
       FIG. 7  is a top plan view of a support foot of the foot assembly shown in  FIG. 1 ; 
       FIG. 8  is cross section taken generally along the line  8 - 8  of  FIG. 7 : 
       FIG. 9  is a perspective view of a retainer member of the foot assembly shown in  FIG. 1 ; 
       FIG. 10  is a perspective view of a jigsaw shown in  FIG. 1 , with a flat plate shown in position to be attached to the support foot of the foot assembly; and 
       FIG. 11  is a perspective view of a jigsaw shown in  FIG. 1 , with a flat plate attached to the support foot of the foot assembly. 
   

   DETAILED DESCRIPTION 
   Turning now to the drawings, and particularly  FIG. 1 , a jigsaw, indicated generally at  10 , has a housing  12  which encloses a motor such as an AC, DC, or universal motor, which is mechanically linked to and drives a reciprocating saw blade  14 . An on/off switch  16  controls the motor, which is powered by an electrical source via cord  18 . Alternatively, the jigsaw  10  may be configured to be powered by a battery pack as is known by those of ordinary skill in the art. Also, those who are knowledgeable in the art will appreciate that other components of jigsaws are generally known, and are not discussed in detail herein. 
   The jigsaw  10  has a foot assembly, indicated generally at  20 , which is secured to the jigsaw housing  12  in a manner whereby it can be tilted, i.e., angularly adjusted relative to the blade  14 . The foot assembly  20  can be adjusted to provide a perpendicular cut relative to the work piece or a 45° bevel cut in either direction. The angular adjustment of the foot assembly is easily made and requires no tools to be carried out. The user merely needs to push the foot assembly forwardly to release its locking mechanism and then tilt the foot assembly relative to the housing in one direction or the other and it will then be locked in a 45° bevel orientation. 
   It should be understood that while the illustrated embodiment will permit the angular positions of 0 and 45° in either direction, the foot assembly may be modified to provide other bevel angles, such as 22-½° , for example, if desired. In addition to the ease of operation of the present invention, it securely locks the angular orientation that is chosen so that there is little likelihood that the foot assembly can be unintentionally changed during operation. Also, the locking mechanism has a robust construction and should not be an impediment to a long useful life for the jigsaw. 
   The foot assembly  20  has a support foot  22  that has a generally flat bottom surface  24  which contacts a work piece that is being cut. The support foot  22  is preferably made of steel that is cut and stamped into its ultimate shape as shown in the drawings. As shown in FIGS.  1 , 6  and  7 , the support foot  22  has a front opening  26 , upturned sidewalls  28  and upturned front wall segments  30 . Since during making curved cuts, the support foot will be moved sideways as well as forwardly, the upturn sidewalls as well as the front wall segments  30  contributes to smooth movement of the jigsaw over the work piece surface. By having a curved portion at the interface between the bottom surface and the sidewalls and front walls, there is less likelihood that an edge of the jigsaw will be caught by a work piece during operation. 
   As shown in  FIG. 6 , the opening  26  has an enlarged curved portions  32  on opposite sides of the opening which are centered around the position of the blade  14 . The enlarged portion enables the foot assembly to be moved to either of the 45° bevel positions and not have the blade contact the support foot  22 . In other words, the necessary clearance is provided by the enlarged portions  32 . 
   The support foot  22  also has a front opening  34  and a rear opening  36  which are produced as the result of a cutting and/or stamping operation whereby the metal that was present before cutting is bent to form an upwardly directed perpendicular front support  38  and rear support  40 . Each of the supports  38  and  40  has a main aperture  42  sized to receive an elongated rod  44  which provides an axis about which the foot assembly can rotate to be tilted between the desired positions. The rod  44  extends beyond both supports  38  and  40  and is retained by suitable recesses in the housing that are appropriately sized to hold the rod  44  firmly in place. In this regard, the housing  12  is preferably fabricated from two half sections, one of which is clearly visible in several of the drawings, including  FIG. 1 . 
   As is also evident from  FIG. 1 , the free ends of the supports  38  and  40  have a generally semi-circular outer shape which enables the support foot  22  to be rotated within the housing  12 . The front support  38  also has a number of spaced apart positioning apertures  46   a - e  that are arranged in a semi-circular configuration that is also concentric with the rod  44 . 
   The foot assembly  20  has a retainer member  48  best shown in  FIG. 8 , that has a top portion  50 , a pair of wing portions  52  and a main portion  54 , the latter of which has an aperture  56  sized to receive the rod  44 . The member  48  also has three protrusions  58 ,  58  that are also spaced from one another and are aligned in a semi-circular orientation concentric with the opening  56  so that they match up with the positioning apertures  46   a  through  46   e.    
   As best shown in  FIG. 3 , the retainer member  48  is configured to fit within complementary recesses in the housing  12  so that when both housing sections are combined, the retainer member  48  will be firmly held in place. Because of the stresses that may be applied to the retainer member  48  during use, it is preferred that it be made of steel or other strong durable material. The member may be unitarily formed or cast with the protrusions being part of the casting or the casting may not include the protrusions  58 , with those being separately fabricated and being force fit into suitable openings in the main portion  54 . 
   A compression spring  60  fits over the rod  44  and bears against the face of the rear support  40  and against the side of the retainer member  48 . The spring is preferably sized to provide a biasing force that is not easily overcome during normal use. Stated in other words, the spring force should be sufficient to keep the foot assembly in a stable locked position and not be accidentally changed during normal use. In this regard, a spring having force characteristics of about 35 Newtons to lock the foot assembly and about 50 Newtons to fully disengage the protrusions  58  from the positioning apertures  46  has been found to be effective. 
   When the foot assembly is in the normal perpendicular cutting operating position as shown in  FIG. 3 , the protrusions  58  are inserted in positioning apertures  46   b ,  46   c  and  46   d  as shown. If the support foot  22  is pushed forwardly to disengage the protrusions  58  from the apertures  46  as shown in  FIG. 4 , the support foot  22  is free to be rotated to one of the 45° tilted positions, such as shown in  FIG. 5 . When the support foot  22  is released, the protrusions  58  will engage positioning apertures  46   c, d  and  e,  as shown in  FIG. 6 . 
   With any of the three possible positions that the support foot can be placed in, each of the three protrusions  58  will be inserted into one of the positioning apertures  46 . This provides a stronger configuration than would occur if only a single or two protrusions were used and thereby also contributes to the strength of the connection and useful life of the product. 
   An alternative embodiment can include a removable transparent flat plate, indicated generally at  62 , and shown in  FIGS. 10 and 11 , that attaches to said support foot  22  and has a faux laser line  64  on a front end portion  66  that functions as a cutting aid since it is preferably exactly in line with plane of the blade  14 . The plate is preferably made from a strong transparent plastic or plastic-like material such as polycarbonite or ABS. Polycarbonite is preferred because it has excellent impact resistant qualities and high strength. To contribute to its strength, the plate preferably has upturned side portions  68  that fit around the side portions  28  of the support foot. As shown in  FIG. 11 , the front portion  66  extends forwardly of the front wall portions  30  of the support foot  22  so that the faux laser line  64  is easily visible to the user. The line  64  may be raised and painted or otherwise colored red (or other appropriate color) to approximate the appearance of a line generated by a laser. An elongated opening  70  is provided to permit the blade to extend through the plate. The elongated opening is preferably sized so that the plate can be attached to the support foot  22  without having to manipulate the blade height or remove it. 
   To attach the plate  62  to the support foot  22 , a pair of front retaining hooks  72  extend upwardly from the front portion thereof for engaging the upper edge of the front walls  30  of the support foot  22 , and a pair of deflectable clips  74  are located at the rear portion thereof for engaging a rear edge of support foot. The clips  74  have a tab  76  that can be pressed by the user to deflect the clips  74  so that a retaining edge which engages the rear edge of the support foot can be released. This enables the clips  74  of the back portion of the plate to clear the support foot  22  and enable the plate to be moved forwardly so that the hooks can be separated from the front wall portions  30 . The hooks  72  and clips  74  are preferably integrally formed during the molding of the plate  62 , although they may also be independently formed and adhesively attached or sonically welded if desired. 
   It will be appreciated that although discussion and description has been made herein of a particular tool and housing embodiment, such treatment has been made only to illustrate the invention. Other invention embodiments and equivalents to various features of the invention as described will be apparent to those skilled in the art. Also, in considering the jigsaw  10  and the foot assembly  20 , it will be appreciated that exemplary embodiments of the present invention are directed to a tool such as the jigsaw  10 , while others are directed only to the foot assembly  20 . Indeed, those knowledgeable in the art will appreciate that the foot assembly  20  will provide benefits and advantages when used with power tools other than a jigsaw. 
   While various embodiments of the present invention have been shown and described, it should be understood that other modifications, substitutions and alternatives are apparent to one of ordinary skill in the art. Such modifications, substitutions and alternatives can be made without departing from the spirit and scope of the invention, which should be determined from the appended claims. 
   Various features of the invention are set forth in the following claims.