Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to sheet bending brakes and
particularly to portable sheet bending brakes.
Background and Summary
_ _of_-the_I Kenton
In the handling of sheet material such as is used
for Baldwin construction, it has been common ion recent limes
to provide a portable sheet bending brake wherein sheet mate-
fiat is clamped between an anvil member and a clamping surface
and a bending member is hinged for bending the sheet material
about the anvil member. Typical sheet bending brakes are
disclosed in United States Patents 3,161,223, 3,481,174,
3,482,427, 3,559,444, 3,817,075 and 4,240,279~
As shown, for example, in the aforementioned United
States Patents 3,161,223, 3,559,444, 3,817,075 and 4,240,279,
the anvil member is clamped into position by means of a backing
plclte that has inclined cams underlying a portion owe the fixed
frame so that when the plate is moved longitudinally by a hand
lever, the cams are moved into and out of position clamping
and unclamping the bikini plate.
In the aforementioned United States Patents 3,481,174
and 3,482,427, the anvil is supported by pivoted bars that,
in turn, are connected by links to a handle that is pivoted
on the frame of the brake so that rotation of the handle moves
the bars and, in turn, the anvil into and out of clamping
pustule.
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the cam to the desired adjusted position and moving the cam
axially to reengage the teeth.
description of the Drawings
FIG. 1 is a fragmentary perspective view of a
sheet bending brake embodying the invention.
FIG. 2 is a fragmentary part sectional rear Elena-
tonal view.
FIG. 3 is a fragmentary sectional view taken along
the line 3-3 in FIG. 2.
FIG. 4 is a perspective view of a portion of the
sheet bending brake during adjustment.
FIG. 5 is an enlarged view of a portion of the
brake.
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it has also heretofore been suggested -that eccentric
cams be utilized for moving the anvil member into end out of
position as shown, for example, in United States Patents
3,383,899, 4,092,841 and 4,081,986.
One of the problems with prior sheet bending brakes
utilizing eccentric cams is that of adjusting the cams on
the shaft. Thus, it is common to provide some type of clamp
for holding -the cams in position. Any such arrangement
results in difficult in adjustment and also -the tendency
of the clamp arrangement to loosen resulting in a loss of
adjustment.
In one arrangement, the cams are adjustable mounted
by bolts which can be loosened to permit rotation of the cams
about the shaft. Such an arrangement operates satisfactorily
but is subject to loss of adjustment in use necessitating
frequent adjustment.
Accordingly, among the objectives of the present
invention are to provide a portable sheet bending brake
incorporating a construction wherein the eccentric cam
positions can be readily adjusted and will remain adjusted;
which is low in cost; and which can be adjusted without the
use of heavy tools.
In accordance with the invention, the shaft and
eccentric cams are provided with circumferential spaced
teeth extending axially so that the cams are locked in any
adjusted position. The position of a cam can be adjusted by
moving the cam axially relative to the shaft -to disengage
the teeth on the cam from the teeth on the shaft, rotating
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Description
Referring to FIGS. 1, 2 and 3, the sheet bending
braze embodying the invention comprises a plurality of long-
tudinally spaced C-shaped frame members 10 which are preferably
injection molded of reinforced plastic such as 30~ glass filled
nylon. Each frame member 10 includes a lower arm 11 and an
upper arm 12 with a connecting portion 13, the upper arm 12
being shorter than -the lower arm 11. Each frame member 10
includes a rearwardly extending recess or notch defined by a
horizontal surface 14 and a vertical surface 15 for receiving
an extruded aluminum square rear rail 16. As shown in FIG.
2, portion 13 includes laterally extending flanges 17 over-
lying the upper surface of the rear rail 16 through which
screws 18 extend to fasten the rear rail to the frame members.
A firs-t fixed extruded aluminum member 20 is pro-
voided on the front end of the lower arms 11 as presently
described and comprises an upper generally triangular portion
21 defining a horizontal clamping surface 22 and a lower C-
shaped portion 23 that has upper and lower walls that tote-
scope over -the free ends of the lower arms Al. Screws fasten
the fixed member 20 on the arms 11.
An extruded aluminum bending member I is hinged -to
a portion of the fixed member 20 by a hinge defined by inter-
meshing projections on the members I 20, respectively.
A hinge pin extends through aligned openings in the project
lions to complete the hinge. The bending member 24 further
includes a laterally extending L-shaped portion 25 that
receives the lower end ox an extruded floating member 26
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yieldingly urged by a spring 26 against the hinge. The member
26 engages the sheet to be bent and minimizes marring during
the bending as more fully described in United States Patents
3,481,174 and 3,482,427. The bending member 24 further includes
a C-shaped portion that supports an adapter 36 for receiving a
tubular handle 27.
The sheet bending brake further includes a plurality
of extruded aluminum bars 30, a bar 30 being pivoted to each
frame member 10 by a bolt 31 at the area of juncture of the rear
of the arm 12 and the upper part of the connecting portion 13.
Each bar 30 includes an upper flange 32, a lower flange 33, and
a vertical wall 34. An extruded aluminum shaft 35 it journal led
in the forward ends of the upper arms 12 by plastic bearings
and extend through enlarged openings in the vertical walls of
the bars 300 A plurality of plastic eccentric cams 36 are fixed
on shaft 44 so that they are positioned between the upper and
lower flanges 32, 33 of each bar. Each frame member 10 has
axially extending bosses surrounding the opening through which
shaft 35 extends. A collar 37 holds shaft 35 axially against
a boss.
The bars 30 support an anvil member 39 that includes
an upper horizontal portion bolted to the lower flange 33 of
the bars, an inclined portion and a V-shaped nose portion
having a horizontal bottornsurface and an inclined uppersurEace.
Ago shown in FIG. 3, a protective strip 40 of sheet
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3~3~
metal such as rolled stainless steel is provided.
A handle 41 is provided for rotating the shaft 44
to rotate cams 45 to move anvil member 60 into and out of
c].arnpiny relation to surface 22. The handle 41 comprises a
U-shaped tune.
The sheet bandanna brake heretofore described is
substantially like that described in pending Canadian
pa-tent application Serial No. 423,598 filed March 15,
1983.
In accordance with the invention, the shaft and
eccentric earns are provided with circumferential spaced
teeth extending axially so -that the cams are locked in any
adjusted position. The position of a cam can be adjusted by
moving the earn axially relative to -the shaft to disengage
the teeth on the cam from the teeth on the shaft, rotating
the cam to the desired adjusted position and moving the cam
axially to reengage -the -teeth.
More specifically shaft 35 is formed with axially
extending grooves 45 defining teeth 46 and a collar 47 having
complementary teeth 48 is provided on -the shaft 35 with -the
teeth 98 enraging the teeth 46. Each cam 36 has an eccentric
opening formed with a plurality of V-shaped teeth 49 which
engacJe complementary V-shaped teeth 50 on collar 47.
In order to adjust the cam positions on shaft 35,
each earn 36 is moved axially relative to -the shaft 35 to disk
enlace the teeth 99, 50, is thereafter rotated to the desired
adjusted position and moved axially to reengage the -teeth 49,
50. The number of teeth 99, 50 is such that small accurate
adjustments can be made. For example, the size of the teeth
can be such as to provide 5 increments of adjustment. The
lower flange 33 of each bar 30 is made sufficiently wide -to
permit the cam 36 to be disengaged. A retainer 51 is removably
fastened to the upper flange 32 by a screw 52 and has a downwardly
extending lip 53 which retains the cam 36 against axial move-
mint during normal operation. During adjustment, the retainer
is removed and a screw 54 holds the collar I against axial
movement when the cam 36 is moved axially to disengage the
teeth.
The number of teeth can vary but, as shown in the
drawings comprises two opposed arcuate segments separated by
arcua-te areas aye, 49b without teeth which have an arcuate
extent of approximately thirty degrees.
It can thus be seen that there has been provided
a sheet bending brake wherein the positions of the eccentric
cams can be readily adjusted and will remain adjusted, which
is low in cost, and which can be adjusted without the use of
heavy tools.
