Guide fence for power tools

A guide fence providing an adjustable gap for accommodating variously configured cutting mechanisms which includes (i) a plurality of longitudinally elongated members having a generally V-shaped cross-section, and (ii) a means for releasable coupling a plurality of nested elongated members so as to create a planar guiding surface from a first lateral side of the nested members.

FIELD OF THE INVENTION 
Broadly, the invention relates to guide fences for power tools. 
Specifically, the invention relates to guide fences which provide a 
central gap for accommodating a rotating cutting mechanism. 
BACKGROUND OF THE INVENTION 
Guide fences are employed with a wide variety of power tools where a 
workpiece is moved relative to a stationary cutting mechanism. The guide 
fence provides a straight surface against which the workpiece may be 
guided in order to ensure a uniform cut. 
A first type of guide fence provides a continuous guiding surface which 
clamps to the table of the power tool by releasable clamping mechanisms 
located at the longitudinal ends of the guiding surface. Such guide fences 
are well suited for use in connection with power tools which require a 
guiding surface remotely positioned from the cutting mechanism, such as a 
bench saw. However, such guide fences are not suited for use in connection 
with power tools which require a guiding surface aligned with the cutting 
mechanism. 
A second type of fence guide suited for use in connection with power tools 
which require a guiding surface aligned with the cutting mechanism employs 
a guiding surface with a centrally located gap for accommodating the 
cutting mechanism. The central gap is generally provided by either 
removing a section from a single continuous guiding surface or employing 
two separate guiding surfaces. The central gap is generally sized as small 
as possible to reduce the risk of misalignment as the workpiece passes 
over the gap while accommodating the largest cutting mechanism capable of 
being used in the tool. However, because of the substantial differences in 
the sizes of cutting mechanisms typically employable in power tools, the 
gap is often considerably larger than that necessary to accommodate the 
particular cutting mechanism being employed. 
Accordingly, a substantial need exists for a guide fence capable of 
providing a central gap which can be readily adjusted to customize the 
size and shape of the gap to a particular cutting mechanism. 
SUMMARY OF THE INVENTION 
We have developed a guide fence for power tools which provides a guiding 
surface with a gap which can be readily adjusted to customize the size 
and/or shape of the gap to a particular cutting mechanism. 
A particular guide fence capable of providing the desired adjustability 
includes (i) a plurality of longitudinally elongated members having a 
first transverse surface which is laterally convex and a second transverse 
surface diametrically opposed to the first transverse surface which is 
laterally concave, and (ii) a means for releasably coupling at least two 
members which are nested with the convex surface of one member nested 
within the concave surface of a second member such that a flat guiding 
surface is formed from the first lateral sides of the nested members.

DETAILED DESCRIPTION OF THE INVENTION INCLUDING A BEST MOLD 
The guide fence produces a flat guiding surface with an adjustable central 
gap from a pair of identical fence assemblies. The fence assemblies are 
readily adjustable to customize the size and shape of the gap to a 
particular cutting mechanism. 
The guide fence is particularly well suited for utilization in conjunction 
with a wood shaper. Accordingly, without intending to be limited thereby, 
the guide fence will hereinafter be referenced with respect to utilization 
in conjunction with a wood shaper. 
NOMENCLATURE 
100: guide fence 
101: longitudinal direction 
102: lateral direction 
103: transverse direction 
200: fence assembly 
210: small fence segments 
210m: length of small fence segments 
210w: width of small fence segments 
210t: thickness of small fence segments 
211: top of small fence segments 
211a: apex at top of small fence segments 
212: bottom of small fence segments 
212a: nadir at bottom of small fence segments 
213: inner end of small fence segments 
214: outer end of small fence segments 
215: front of small fence segments 
215a: a front leg of small fence segments 
216: rear of small fence segments 
216a: rear leg of small fence segments 
220: large fence segments 
220m: length of large fence segments 
220w: width of large fence segments 
220t: thickness of large fence segments 
221: top of large fence segments 
221a: apex at top of large 
221i b: front top portion of large fence segments 
222: bottom of large fence segments 
222a: nadir at bottom of large fence segments 
223: inner end of large fence segments 
224: outer end of large fence segments 
225: front of large fence segments 
225a: front leg of large fence segments 
226: rear of large fence segments 
226a: rear leg of large fence segments 
227: front channel on large fence segments 
228: rear channel on large fence segments 
230: guiding surface 
250: central gap between fence assemblies 
300: segment clamp 
303: inner end of segment clamp 
304: outer end of segment clamp 
310: base of segment clamp 
311: top of segment clamp base 
311a: apex at top of segment clamp base 
320: sidewall of segment clamp 
321: front surface of segment clamp sidewall 
322: orifice through segment clamp sidewall 
323: threaded holes in inner end of segment clamp 
330: top of segment clamp 
330a: top front portion of segment clamp 
330b: top rear portion of segment clamp 
331: flex line 
332: pivotable contacting surface of segment clamp 
341: diagonal channel 
342: orifice through top of segment clamp 
343: channel across top front portion of segment clamp 
350: clamping knob 
351: shaft of clamping knob 
352: handle of clamping knob 
353: flat washers 
354: nuts 
360: direction of clamping force 
400: support half 
401: top of support half 
402: bottom of support half 
403: inner surface of support half 
404: outer surface of support half 
405: front of support half 
406: rear of support half 
410: passageway through support half 
411: slit through outer surface of support half 
412: T-shaped channel along top of support half 
420: cover plate 
421: slits through cover plate 
422: orifices through cover plate 
423: right side of cover plate 
424: left side of cover plate 
500: tube 
501: central bore through tube 
502: orifice through side of tube 
505: front end of tube 
506: rear end of tube 
520: fine tuning knob 
521: central bore through fine tuning knob 
540: tube locking knob 
541: shaft of tube locking knob 
542: handle of tube locking knob 
545: washers 
561: first pair of bolts 
562: second pair of bolts 
600: dust deflector plates 
602: top of dust deflector plates 
602: side of dust deflector plates 
603: orifices through side of dust deflector plates 
700: dust chute 
701: top of dust chute 
703: right side of dust chute 
704: left side of dust chute 
705: front of dust chute 
706: back of dust chute 
711: top front flange on dust chute 
713: right front flange on dust chute 
714: left front flange on dust chute 
715: orifices through right and left front flanges 
716: indent in right and left front flanges 
751: first set of machine screws 
752: flat washers 
753: nuts 
755: second set of machine screws 
757: third set of machine screws 
800: support half locking knob 
801: shaft of fence locking knob 
802: handle of fence locking knob 
803: flat washers 
910: cutting tool 
920: working surface 
921: threaded holes in table 
CONSTRUCTION 
Referring to FIGS. 2 and 3, the guide fence 100 includes a pair of 
identical guide fence assemblies 200 which are placed to the right and 
left of the cutting tool 910 to create a guiding surface 230 with the 
cutting tool 910 accommodated within a gap 250 between the fence 
assemblies 200. Each fence assembly 200 is independently adjustable in 
both the longitudinal 101 and lateral 102 directions. Lateral adjustment 
of the fence assemblies 200 permits lateral alignment of the guide fence 
assemblies 200 with respect to the cutting tool 910 and with respect to 
one another. Longitudinal adjustment permits configuration of the gap 250 
between the fence assemblies 250 about the cutting tool 910. 
Referring to FIGS. 6 and 7, the guiding surface 230 of each fence assembly 
200 is created by a plurality of transversely stacked small fence segments 
210 capped with a large fence segment 220. The small fence segments 210 
are longitudinally elongated members with a generally V-shaped 
cross-section. The top surface 211 of the small fence segments 210 are 
convex with a definitive apex 211a. The bottom surface 212 of the small 
fence segments 210 are concave with a definitive nadir 212a. The front 215 
and rear 216 surfaces of the small fence segments 210 are parallel. The 
top 211 and bottom 212 of the small fence segments 210 provide 
complemental surfaces which accommodate transverse stacking of the small 
fence segments 210 with the top convex surface 211 of one segment 210 
nested within the concave bottom surface 212 of an adjacent segment 210. 
Referring to FIG. 4, transverse stacking of the small fence segments 210 
produces a flat guiding surface 230 from the front surfaces 215 of the 
small fence segments 210. Planar alignment of the front surfaces 215 of 
the stacked small fence segments 210 is achieved by transversely aligning 
the apex 211a at the top 211 of a small fence segment 210 with the nadir 
212a at the bottom 212 of the small fence segment 210 such that a plane 
encompassing the apex 211a and the nadir 212a is parallel to the front 
surface 215 of the small fence segment 210. 
The top 211 and bottom 212 surfaces of the small fence segments 210 are 
smooth so as to permit transversely stacked segments 210 to be 
independently slipped past one another in the longitudinal direction 101. 
The ability to independently move the small fence segments 210 in the 
longitudinal direction 101 permits the inner ends 213 of the small fence 
segments 210 to define substantially any desired gap 250 configuration 
within limits established by the thickness 210t of the small fence 
segments 210. 
A sufficient number of small fence segments 210 should be provided in each 
fence assembly 200 to permit shaping of the fence assembly 200 from the 
working surface 920 to the top of the cutting tool 910. Hence, the number 
of small fence segments 210 which should be employed in each fence 
assembly 200 depends upon a combination of the height of the cutting tool 
910 above the working surface 920 and the thickness 210t of the small 
fence segments 210. Typical power tools which require a guiding surface 
230 aligned with the cutting tool 910 have a cutting tool 910 which 
extends about 0.5 cm to about 10 cm above the working surface 920. The 
small fence segments 210 preferably have a thickness of about 0.2 to about 
1 cm as small fence segments 210 of less than about 0.2 cm are difficult 
to manufacture, easily damaged, and increase the difficulty of assembling 
and adjusting the fence assembly 200 while small fence segments 210 having 
a thickness 210t of greater than about 1 cm do not provide sufficient 
conformability about the cutting tool 910 and can result in substantial 
spaces between the inner ends 213 of the small fence segments 210 and the 
cutting tool 910 despite longitudinal adjustability of the fence segments 
210. 
Accordingly, about three to about twenty small fence segments 210 having a 
thickness of about 0.2 to about 1 cm is generally effective for achieving 
the desired degree of adjustability. 
Referring to FIG. 7, a large fence assembly segment 220 is provided with 
each fence assembly 200 for placement at the top of a stack of small fence 
segments 210 for increasing the height of the guiding surface 230 after 
the guiding surface 230 is above the cutting tool 910. As with the small 
fence segments 210, the large fence segments 220 are longitudinally 
elongated members with a generally V-shaped cross-section and define (i) a 
convex top surface 211 with a definitive apex 211a, (ii) a concave bottom 
surface 212 with a definitive nadir 212a, and (iii) parallel front 215 and 
rear 216 surfaces. 
Longitudinally extending central channels 227,228 are respectively provided 
in the front 225 and rear 226 of the large fence segments 220 for 
controlling the size and weight of the large fence segments 220 while 
still providing a planar guiding surface 225 proximate the top 221 and 
bottom 222 of the large fence segments 220. 
The thickness 220t of the large fence segments 220 is preferably about 2 to 
5 cm. 
Selection of the width 210w,220w of the small 210 and large 220 fence 
segments requires a balancing of the competing interest of cost (increased 
width=increased cost), structural integrity (increased width=increased 
structural integrity), and stacked stability (increased width=increased 
stacked stability). Generally, a width of about 1 to about 3 cm provides 
an appropriate balancing of these competing interests. 
Likewise, selection of the length 210m,220m of the small 210 and large 220 
fence segments requires a balance of the competing interests of cost 
(increased length=increased cost), functionality (increased 
length=increased functionality as a guiding surface), and risk of 
deviations (increased length=increased risks of deviations and 
imperfections in the guiding surface). Generally, a length 210m,220m of 
about 20 to about 50 cm provides an effective balance between these 
competing interests. 
Referring to FIGS. 1,2 and 4, each fence assembly 200 is clamped into 
position by a segment clamp 300. The base 310 of the segment clamp 300 has 
a V-shaped top surface 311 with a definitive apex 311a for nesting within 
the concave bottom surface 212 of a small fence segment 210. A vertical 
side wall 320 extends upwardly from the base 310 of the segment clamp 300 
to provide a planar front surface 321 against which the rear surfaces 
216,226 of the fence segments 210,220 may be constrained. Because the 
front 215,225 and rear 216,226 surfaces of the fence segments 210,220 are 
parallel, such planar constrainment of the rear surfaces 216,226 of the 
fence segments 210,220 causes the front surfaces 215,225 of the fence 
segments 210,220 to produce a planar guiding surface 230. 
The fence segments 210,220 are configured with a rear leg 216a,226a which 
is slightly shorter than the front leg 215a,225a as the rear leg 216i a of 
the lowermost small fence segment 210 must accommodate connection of the 
base 310 to the sidewall 320 while the front leg 215a preferably extends 
into contact with the working surface 920. 
The top 330 of the segment clamp 300 includes a front portion 330a and a 
rear portion 330b separated by a diagonal channel 341. The diagonal 
channel 341 creates a longitudinal flex line 331 across the top 330 of the 
segment clamp 300 about which the front portion 330a may be laterally 
pivoted with respect to the rear portion 330b. 
Pivoting of the top front portion 330a of the segment clamp 300 with 
respect to the top rear portion 330b is effected by a pair of 
longitudinally spaced clamping knobs 350. The shaft 351 of each clamping 
knob 350 extends laterally through an orifice 342 which passes through 
both the top front 330a and top rear 330b portions of the segment clamp 
300 and threadably engages a nut 354 retained within a channel 343 in the 
top front portion 330a of the segment clamp 300. The nut 354 is retained 
within the channel 343 such that the nut 354 is not rotated by rotation of 
the shaft 351. 
Referring to FIG. 5, the contacting surface 332 of the top front portion 
330a exerts a clamping force upon the stacked fence assembly 200 at 
approximately a 45.degree. angle towards the base 310 and sidewall 320 of 
the segment clamp 300 so as to simultaneously coerce the fence segments 
210,220 against the base 310 and sidewall 320 of the segment clamp 300. 
The clamping knobs 350 are include wratchet style handles 352 which permit 
the handle 352 to be placed in either a first operable mode for rotatably 
driving the shaft 351 or a second operable mode for rotatably 
repositioning the handle 352 about the shaft 351. Such wratchet-style 
levers are readily available from a number of suppliers including Jergens 
Distrubutors of Cleveland, Ohio. 
Referring to FIG. 2, each segment clamp 300 is laterally coupled to the 
front end 705 of a tube 500 by the means of a threaded bolt 562 which 
extends through one of two longitudinally spaced apertures 322 in the side 
wall 320 of the segment clamp 300 and into a threaded central bore 501 in 
the tube 500. The apertures 322 through the side wall 320 of the segment 
clamp 300 are recessed to insure that the bolt 562 does not interrupt the 
planar front surface 321 of the side wall 320. The pair of apertures 321 
permits longitudinal positioning of the segment clamp 300 and fence 
assembly 200. 
Each tube is slidably retained within the central passageway 410 of a 
support half 400. 
The threaded shaft 541 of a tube locking knob 540 extends through a slit 
411 in the outer surface 404 of the support half 400 and into a threaded 
orifice 502 in the side of the tube 500. When tightened, the tube locking 
knob 540 retains the tube 500 in position with respect to the support half 
400. When loosened, the tube locking knob 540 permits limited lateral 
repositioning of the tube 500 within the central passageway 410 based upon 
the lateral length of the slit 411 in the outer surface 404 of the support 
half 400. 
The support halves 400 are coupled together by a cover plate 420. The cover 
plate 420 is attached to each support half 400 by a pair of machine screws 
751 which extend through a pair of laterally spaced orifices 422 proximate 
each side 423,424 of the cover plate 420 and threadably engage a nut 753 
retained within a T-shaped channel 412 in the top 401 of the support 
halves 400. The T-shaped channel 412 retains the nut 753 such that the nut 
753 is not rotated by rotation of the machine screw 751 and is 
transversely restrained from moving towards the cover plate 420. 
An L-shaped dust deflector plate 600 is coupled to the inner end 303 of 
each segment clamp 300 by a pair of machine screws 755 which extend 
through a pair of transversely spaced orifices 603 in the side 602 of the 
dust deflector plate 600 and into threaded holes 323 in the inner end 303 
of the segment clamp 300. 
The dust deflector plates 600 define the top 601 and sides 602 of a 
laterally extending passageway (unnumbered) extending from the segment 
clamps 300 to a dust chute 700. 
The dust chute 700 is open at the front 705 and bottom (unnumbered) and 
tapers from front 705 to back 706. The dust chute 700 sets upon the 
working surface 920 with the back 706 of the dust chute 700 extending 
slightly beyond the edge of the table 920 so as to create a passageway 
(unnumbered) extending through the duct chute 700 from front 705 to back 
706 with intake through the open front 705 and venting through the open 
bottom between the back 706 of the dust chute 700 and the edge of the 
working surface 920. 
Flanges 713,714 extend from the sides 703,704 of the dust chute 700 for 
connecting the dust chute 700 to the support halves 400 with machine 
screws 757. The machine screws 757 extend through a pair of transversely 
space orifices 715 in each side flange 713,714 and into threaded holes 
(not shown) in the rear 406 of the support halves 400. 
A fine tuning knob 520 is rotatably secured to each side flange 713,714 of 
the dust chute 700 within a circular indentation 716 in the side flanges 
713,714 so as to prevent lateral movement of the fine tuning knob 520 
relative to the dust chute 700. Each fine tuning knob 520 is also 
connected to the rear end 506 of one of the tubes 500 by a bolt 561 which 
extends through a central bore 521 in the fine tuning knob 520 and into a 
threaded portion of the central bore 501 in each tube 500. The bolts 561 
connect the fine tuning knobs 520 and tubes 500 such that rotation of a 
fine tuning knob 520 causes the associated bolt 561 to rotate within the 
central bore 501 of the associated tube 500 and thereby cause the tube 500 
to be laterally repositioned within the central passageway 410 in the 
support half 400. 
A top front flange 711 extends upwardly from the top 701 of the dust chute 
700 for providing continuity betwee the dust deflector plates 600 and the 
dust chute 700. 
The guide fence 100 is secured to the working surface 920 by means of a 
pair of support half locking knobs 800. The shaft 801 of each support half 
locking knob 800 is coupled to a handle 802 at one end and threaded at the 
other end. The threaded end of the shaft 801 transversely extends through 
a laterally elongated slit 421 in the cover plate 420 and is threadably 
inserted into a threaded hole 921 in the working surface 920. The lateral 
size of the slits 421 dictate the extent to which the cover plate 420 may 
be laterally repositioned with respect to the working surface 920. 
In use, the support halves 400, cover plate 420, fine tuning knobs 520, and 
dust chute 700 are permitted/prevented from moving laterally with respect 
to the working surface 920 by support half locking knobs 800 while the 
fence assemblies 200, segment clamps 300, tubes 500 and dust deflectors 
plates 600 are permitted/prevented from moving laterally with respect to 
the support halves 400 by tube locking knobs 540. 
The components of the fence assembly 200 may be constructed from any 
material possessing sufficient structural integrity including metals such 
as steel and aluminum and plastics such as polyester and polyvinyl 
chloride. 
OPERATION 
Initial positioning of the guiding surfaces 230 on the guide fence 100 
includes the steps of (i) securing the segment clamps 300 to the tubes 500 
with a bolt 562 by passing the bolt 562 through whichever of the orifices 
322 in the sidewall 320 of the segment clamps 300 causes the segment clamp 
300 to clamp closest to the longitudinal center of the large fence segment 
220 retained within the segment clamp 300 when the large fence segment 220 
is operably positioned, (ii) stacking the small 210 and large 220 fence 
segments upon the bases 310 of the segment clamps 300, (iii) tightening 
the clamping knobs 350 until the contacting surfaces 332 of the segment 
clamps 300 securely contact the front top portions 221b of the large fence 
segments 220 and force the rear surfaces 216,226 of the stacked fence 
segments 210,220 within the segment clamp 300 against the front surface 
321 of the segment clamp sidewall 320, (iv) placing a straight edge (not 
shown) against the guiding surfaces 230 of both fence assemblies 200, (v) 
independently adjusting the lateral position of each fence assembly 200 by 
rotating the associated fine tuning knob 520 until the guiding surface 230 
of the fence assemblies 200 are longitudinally aligned with the straight 
edge, (vi) tightening the tube locking knobs 540 to secure the tubes 500 
to the support halves 400, (vii) laterally positioning the support halves 
400 with respect to the cutting tool 910 by moving the entire guide 
assembly 100, and (viii) tightening the support half locking knobs 800 to 
secure the support halves 400 against the working surface 920. 
The specification is provided to aid in a complete nonlimiting 
understanding of the invention. Since many variations and embodiments of 
the invention may be made without departing from the spirit and scope of 
the invention, the invention resides in the claims hereinafter appended.