U.S. patent application number 10/119277 was filed with the patent office on 2002-08-29 for blades for hand held power operated shears.
Invention is credited to Herrmann, Raymond J., Zimmermann, Arthur W..
Application Number | 20020116824 10/119277 |
Document ID | / |
Family ID | 22454440 |
Filed Date | 2002-08-29 |
United States Patent
Application |
20020116824 |
Kind Code |
A1 |
Herrmann, Raymond J. ; et
al. |
August 29, 2002 |
Blades for hand held power operated shears
Abstract
A hand-held power-operated blade-actuating or other work member
actuating device, especially useful as shears for processing
comestible products such as fowl. A servo mechanism and linkage
connected with a movable blade and a finger control causes
controlled powered movement of the blade in coordination with the
finger control. A fixed blade and a pivoted blade are insertable
and removable as a unit from a hand-held frame in which the fixed
blade is restrained against rotation relative to the frame. The
blades and frame are constructed so the blades are insertable or
removable only when closed. In a preferred embodiment the fixed
blade is retained in part by two load bearing pins extending from
the frame and located substantially diametrically opposite each
other relative to the pivot axis of the movable blade.
Inventors: |
Herrmann, Raymond J.;
(Westlake, OH) ; Zimmermann, Arthur W.; (Bay
Village, OH) |
Correspondence
Address: |
WATTS, HOFFMANN,
FISHER & HEINKE CO., L.P.A.
Suite 1750
1100 Superior Ave.
Cleveland
OH
44114
US
|
Family ID: |
22454440 |
Appl. No.: |
10/119277 |
Filed: |
April 9, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10119277 |
Apr 9, 2002 |
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09291228 |
Apr 13, 1999 |
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6367156 |
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09291228 |
Apr 13, 1999 |
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08330183 |
Oct 27, 1994 |
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08330183 |
Oct 27, 1994 |
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08132526 |
Oct 6, 1993 |
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5375330 |
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Current U.S.
Class: |
30/228 ; 30/249;
30/250; 30/254; 30/260; 30/266 |
Current CPC
Class: |
Y10T 137/87056 20150401;
Y10T 137/86919 20150401; B25B 7/12 20130101; B26B 13/04 20130101;
B25B 7/126 20130101; B26B 15/00 20130101 |
Class at
Publication: |
30/228 ; 30/249;
30/250; 30/254; 30/260; 30/266 |
International
Class: |
B26B 013/04; B26B
015/00 |
Claims
Having described a preferred embodiment of the invention, we
claim:
1. A pair of replaceable blades for a hand-held power-operated
blade-actuating device, said blades without handles and having
cooperating edges for cutting, said pair of blades comprising a
first blade having a cutting portion and having a mounting portion
by which the first blade can be fixed relative to a support and a
second blade having a cutting portion and an actuating portion and
constructed to be pivoted relative to the support and the first
blade at a location on the second blade between the cutting portion
of the second blade and the actuating portion of the second blade,
a surface forming a part of the actuating portion for operatively
coupling the second blade to a powered actuator, the actuating
portion of said second blade including a portion that is located
relative to the mounting portion of the first blade when the blades
are closed to allow attachment and removal of the blades as an
assembled unit to or from the support, and located when the blades
are open to prevent the attachment or removal of the blades to or
from the support, and a locating surface on the pair of assembled
blades that extends transversely of the general extent of the
blades for engaging with a surface of the support that extends
transversely of the general extent of the blades when the blades
are mounted on the support.
2. A pair of blades as set forth in claim 1 including a heel
portion forming a part of the actuating portion of the second blade
substantially aligned with the cutting edge of the second blade and
having a ride surface facing toward the first blade, a surface on
the first blade opposed to and contacted by the ride surface to
bias the cutting edge of one blade into mutual contact with the
cutting edge of the other blade at a location along each where the
cutting edges intersect.
3. A pair of blades as set forth in claim 2 wherein one of said
ride surface and opposed surface has a portion projecting toward
the other from the general plane of the respective blade to bias
the cutting edge of one blade into mutual contact with the cutting
edge of the other blade at a location along each where the cutting
edges intersect.
4. A pair of blades as set forth in claim 1, 2 or 3 wherein said
coupling surface is formed by a slot in which a movable drive
portion associated with an actuator is receivable, said slot
extending at an obtuse angle with respect to the general extent of
the cutting edge of the second blade and beginning at least within
0.55 inch from the location of the pivot of the second blade and
extending a distance of at least 1.0 inch from the location of the
pivot.
5. A pair of blades as set forth in claim 1 wherein said mounting
portion has an opening to receive a load bearing pin of the support
and serves to inhibit relative movement between said first blade
and the support.
6. A pair of blades as set forth in claim 5 including a second
opening in the mounting portion, said first and second openings
being located substantially diametrically opposite to each other
relative to the location where the second blade pivots relative to
the first blade, to inhibit relative rotation of the first blade
with respect to the support.
7. A pair of blades as set forth in claim 1, 2, 3, 5 or 6 in which
the actuating portion of the second blade includes a portion that
underlies the mounting portion of the first blade when the blades
are closed and that extends from behind the mounting portion when
the blades are not closed, and when extending prevents the
attachment or removal of the blades to or from the support.
8. A pair of replaceable work members for a hand-held
power-operated work member-actuating device, said work members
without handles and having cooperating work surfaces for pressing
against a work piece located between the two work members, said
pair of work members comprising a first member having a working
portion and a mounting portion by which the first member can be
fixed relative to a support and a second member having a working
portion and an actuating portion and constructed to be pivoted
relative to the support and the first member at a location on the
second member between the working portion of the second member and
the actuating portion of the second member, a surface forming a
part of the actuating portion for operatively coupling the second
member to a power-operated actuator, the actuating portion of said
second member including a portion that is located relative to the
mounting portion of the first member when the work surfaces are
closed to allow attachment and removal of the members as an
assembled unit to or from the support, and located when the members
are open to prevent the attachment or removal of the members to or
from the support, and a locating surface on the pair of assembled
members that extends transversely of the general extent of the
mounting and actuating portions of the members for engaging with a
surface of the support that extends transversely of the general
extent of the mounting and actuating portions of the members when
the members are mounted on the support.
9. A pair of work members as set forth in claim 8 including a heel
portion forming a part of the actuating portion of the second work
member substantially aligned with the work surface of the second
work member and having a ride surface facing toward the first work
member, a surface on the first work member opposed to and contacted
by the ride surface to bias the work surface of one work member
into mutual contact with the work surface of the other work member
at a location along each where the cutting edges intersect.
10. A pair of work members as set forth in claim 9 wherein one of
said ride surface and opposed surface has a portion projecting
toward the other from the general plane of the respective work
member to bias the work surface of one work member into mutual
contact with the work surface of the other work member at a
location along each where the cutting edges intersect.
11. A pair of work members as set forth in claim 8, 9 or 10 wherein
said coupling surface is formed by a slot in which a movable drive
portion associated with an actuator is receivable, said slot
extending at an obtuse angle with respect to the general extent of
the work surface of the second work member and beginning at least
within 0.55 inch from the location of the pivot of the second work
member and extending a distance of at least 1.0 inch from the
location of the pivot.
12. A pair of work members as set forth in claim 8 wherein said
mounting portion has an opening to receive a load bearing pin of
the support and serves to inhibit relative movement between said
first work member and the support.
13. A pair of work members as set forth in claim 12 including a
second opening in the mounting portion, said first and second
openings being located substantially diametrically opposite to each
other relative to the location where the second work member pivots
relative to the first work member, to inhibit relative rotation of
the first work member with respect to the support.
14. A pair of work members as set forth in claim 8, 9, 10, 12 or 13
in which the actuating portion of the second work member includes a
portion that underlies the mounting portion of the first work
member when the work members are closed and that extends from
behind the mounting portion when the work members are not closed,
and when extending prevents the attachment or removal of the work
members to or from the support.
15. A hand-held power-operated tool, said tool comprising: first
and second members for performing a desired task upon relative
movement about a pivot axis from a first position towards a second
position, said first member having a mounting portion and said
second member having an actuating portion; a frame for supporting
said members in extending relationship to the frame for relative
pivotal movement; a load bearing pin extending from said frame and
spaced from the pivot axis of said members; an opening in the
mounting portion of said first member to receive said pin; a
thumb-receiving recess in the frame; a finger-operated control
member secured to the frame, relatively movable with respect to the
first and second members and the frame, said control member
extending from the frame in a direction generally opposite to that
of said second member, and said thumb-receiving recess being
located on said frame at a position generally aligned with and
displaced from said first member; an actuator engaged with the
actuating portion of said second member for moving said second
member relative to said first member; and a servo mechanism
controlled by said second member and said finger-operated control
member that controls operation of said actuator to move said second
member relative to said first member in response to movement of
said finger-operated control member.
16. A tool as set forth in claim 15 including a second load bearing
pin extending from said frame and spaced from the pivot axis of
said members and a second an opening in the mounting portion of
said first member to receive said second pin, said two pins and two
openings being located substantially diametrically opposite to each
other relative to the pivot axis.
17. A tool as set forth in claim 15 or 16 including a recess in the
frame in which the actuating portion of the second member moves
when the second member is pivoted with respect to the first member,
and a surface at least in part bounding an opening to the recess,
said opening being a size and shape that said surface allows entry
or removal of the second member to the recess when the members are
pivoted to a closed position and prevents entry or removal when the
first and second members are displaced from a closed position.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This is a continuation-in-part application of copending
application Ser. No. 08/330,183 filed Oct. 27, 1994 which is a
divisional application of Ser. No. 08/132,526 filed Oct. 6, 1993,
now U.S. Pat. No. 5,375,330.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] The present invention relates generally to improved power
operated shears that are useful for industrial cutting
applications. In particular, the improved shears of the present
invention are suitable for use in the food processing industry to
cut and trim meat, and especially to cut poultry.
[0004] 2. Description of the Prior Art
[0005] Hand held manually operated conventional scissors have been
used for cutting and trimming meat and other food products.
Conventional scissors also have been used in a variety of other
industries for cutting sheet material, such as cloth, textiles or
thin metals. It was necessary for an operator of the conventional
scissors to use a relatively large cutting effort and often the
operator's wrist was at an unnatural orientation. Repetitive use at
such orientation and large cutting effort could cause injury to the
operator's wrist. To reduce the effort needed to operate such
conventional scissors, power operated shears have been devised.
[0006] Most known power operated hand held shears have various
shortcomings. For example, most such shears do not have a similar
physical arrangement to conventional scissors, the blade movement
cannot be controlled to the same extent and in the same way as
conventional manually powered shears, the blades are not easily
replaced and the blades, if replaceable, are not reliably retained
in the shears to withstand repeated heavy loading.
[0007] Thus, a need exists for power operated or power assisted
cutting shears that are arranged, operated and controlled in a
manner similar to that of conevntional manually-operated scissors,
and have easily replaceable blades that can withstand the repeated
heavy loading that power operated shears used in a commercial
setting will encounter,
SUMMARY OF THE INVENTION
[0008] The present invention is directed to replaceable blades for
hand held power operated shears used in a commercial setting. The
power operated shears overcome the shortcomings of the known power
operated shears mentioned above and others by being closely similar
in physical arrangement and operation to that of conventional
manually operated scissors. Other operating advantages of the hand
held power operated shears of the present invention include a
controllable rate of closing of blades, a controllable extent of
closing, easily replaceable blades and a reliable load bearing
mounting for one of the blades.
[0009] The present invention is also directed to hand held power
operated tools, and more particularly shears. While the invention
will be described in connection with the preferred shears, it will
be understood that other work members for accomplishing a desired
task can be arranged and operated by a tool in the same or similar
manner as the shear blades.
[0010] The shears include first and second blades for cutting a
workpiece upon relative pivotal movement from a first open position
towards a second closed position. A frame supports the blades for
relative pivotal movement about an axis. A first handle and a
second relatively pivotable handle are provided. One of the handles
is supported for pivoting about an axis independently of the
blades. The pivoting handle extends in a direction relative to the
axis opposite the second blade. The other of the handles extends in
a direction opposite the first blade relative to the axis. An
actuator pivots the second blade relative to the first blade to
impart a cutting action between blades. A servo mechanism is
controlled by movement of the second blade and pivoting handle to
control operation of the actuator to pivot the second blade
relative to the first blade in coordination with movement of the
pivoting handle.
[0011] The blades are readily replaceable. The blades are supported
for relative pivotal movement. One blade is constructed to be fixed
in a supporting frame. The other blade is constructed to be
pivotable relative to the frame and first blade. The pivotable
blade has an actuating portion extending in an opposite direction
from the pivot from a cutting portion of the blade at an obtuse
angle in the range of about 120.degree. to 170.degree. relative to
a portion of the cutting edge.
[0012] The actuating portion of the pivotable blade has a drive
slot that receives a portion of a drive link connected to a piston
rod of the fluid actuator. The length and angle of the actuating
portion of the pivotable blade and the distance the slot length
extends, as well as the location of the pivot, are coordinated with
the drive link to allow a size and arrangement of the parts that
facilitate locating parts in the area of the shears that can be
accommodated by the palm of the operator's hand. The length and
angle of the actuating portion at the same time produces relatively
high leverage between the blade and the fluid actuator over a
cutting excursion of 45 degrees of relative pivoting of the blades.
The provision of relatively high leverage assures lower reaction
forces at the pivot of the blades. Lower reaction forces allow
lower structural weight and longer wear life. Relatively high
leverage also allows the use of a relatively slim actuating
cylinder that can provide adequate force using typical shop air
pressures.
[0013] The pivotable blade has a heel portion forming a part of the
actuating portion. The heel portion has a ride surface facing an
opposed surface of the fixed blade. In one embodiment a part of the
opposed surface of the fixed blade projects toward the ride surface
of the pivotable blade, biasing the cutting edges of the blades
into mutual contact where the cutting edges intersect.
[0014] Thus, the invention herein disclosed and claimed is, in its
principal broad aspects, directed to a pair of replaceable blades
for a hand-held power-operated blade-actuating device. The blades
are without handles, have cooperating edges for cutting, and the
pair comprises a first blade having a cutting portion and having a
mounting portion by which the first blade can be fixed relative to
a support and a second blade having a cutting portion and an
actuating portion and constructed to be pivoted relative to the
support and the first blade at a location on the second blade
between the cutting portion of the second blade and the actuating
portion of the second blade, A surface forms a part of the
actuating portion for operatively coupling the second blade to a
power actuator. The actuating portion of the second blade includes
a portion that is located relative to the mounting portion of the
first blade and the support structure when the blades are closed to
allow attachment and removal of the blades as an assembled unit to
or from the support, and is located when the blades are open to
prevent the attachment or removal of the blades to or from the
support. A locating surface on the pair of assembled blades extends
transversely of the general extent of the blades for engaging with
a surface of the support that extends transversely of the general
extent of the blades when the blades are mounted on the
support.
[0015] The portion of the second blade that allows or prevents
attachment or removal of the blades in one preferred embodiment is
constructed to underlie the mounting portion of the first blade
when the blades are closed and to extend from behind the mounting
portion when the blades are not closed, and when extending is
obstructed by a surface of the support from moving in a direction
along which the blades can be removed from the support.
[0016] In one preferred embodiment a locating surface of the
assembled blades is at the pivot between the blades. In another
preferred embodiment, a locating surface is provided on a mounting
portion of one of the blades, and in its preferred construction,
two apertures are provided, located to lie on substantially
diametrically opposite sides of the pivot for the blades.
[0017] The invention, in its broad aspects applies to work members
other than shears or replaceable cutting blades, but otherwise of
the general description as above.
[0018] Further features of the present invention will become
apparent to those skilled in the art to which the present invention
relates from reading the following descriptions with reference to
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a plan view of hand held power operated shears
embodying the present invention with the handles and blades in
fully closed relative positions;
[0020] FIG. 2 is a view similar to FIG. 1 with parts in fully open
relative positions;
[0021] FIG. 3 is a partial perspective view of the shears in FIG. 1
with parts removed for clarity illustrating the major movable
parts;
[0022] FIG. 4 is a view similar to FIG. 3 illustrating relative
positions of some parts of the shears;
[0023] FIG. 5 is an enlarged perspective view of a frame and handle
portion of the shears in FIG. 1;
[0024] FIG. 6 is an exploded perspective view of a portion of the
shears in FIG. 1 illustrating the frame and the blades;
[0025] FIG. 7 is a perspective view of the portion of the shears in
FIG. 6 with the parts assembled;
[0026] FIG. 8 is an enlarged perspective view of the frame and
handle of the shears;
[0027] FIG. 9 is an enlarged perspective view of the frame and
handle in FIG. 8 viewed from another direction;
[0028] FIG. 10 is a plan view of one replaceable blade of the
shears;
[0029] FIG. 11 is a plan view of another replaceable blade of the
shears;
[0030] FIG. 11A is a plan view of an alternate embodiment of the
blade illustrated in FIG. 11;
[0031] FIG. 12 is a side view of the blade illustrated in FIG. 11
taken along the line 12-12 in FIG. 11;
[0032] FIG. 13 is an enlarged view of an axial end portion of the
blade in FIG. 12;
[0033] FIG. 13A is a view similar to FIG. 13 illustrating an
alternate axial end portion of the blade;
[0034] FIG. 14 is an exploded perspective view of the major movable
parts of the shears in FIG. 1;
[0035] FIG. 15 is a plan view of a fluid power actuator, drive link
and blade of the shears;
[0036] FIG. 16 is an enlarged longitudinal cross-sectional view of
the servo control valve and safety valve of the shears;
[0037] FIG, 17A-H are schematic longitudinal cross-sectional views
of the servo control valve in FIG. 16 illustrated with parts in
different operating positions;
[0038] FIG. 18 is a graph representing the ratio of the change in
blade angle relative to the change in handle angle as a function of
the relative angle between the blades;
[0039] FIG. 19 is an enlarged side elevational view of a frame of
an alternate embodiment and replaceable blades of the invention,
illustrating a load bearing mounting arrangement between one of the
blades and the frame;
[0040] FIG. 19A is a top view of the blades in FIG. 19;
[0041] FIG. 20 is an exploded perspective view of the frame and
blades in FIG. 19, better illustrating the load bearing mounting
arrangement;
[0042] FIG. 20A is a detailed view partly in section of a pivoting
connection for the blades;
[0043] FIG. 21 is a plan view of an alternate embodiment of
replaceable blades;
[0044] FIG. 21A is a top view similar of the blades in FIG. 21;
[0045] FIG. 22 is a plan view of another alternate embodiment of
replaceable blades;
[0046] FIG. 23 is a plan view of another alternate embodiment of
replaceable blades;
[0047] FIG. 24 is a plan view of another alternate embodiment of
replaceable blades;
[0048] FIG. 25 is a plan view of another alternate blade
embodiment; and
[0049] FIG. 26 is a top plan view of the frame of FIG. 19, with the
orientation reversed.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
[0050] Overview
[0051] Hand held power operated shears 20, embodying the present
invention, are illustrated in FIG. 1. The shears 20 include a
pivotable blade 22 which is reciprocable relative to another blade
24 between the fully open position illustrated in FIG. 2 and the
fully closed position illustrated in FIG. 1. A cutting or shearing
action is provided between the cutting edges 42, 44 (FIG. 2) of the
blades 22, 24, respectively, during movement of the pivotable blade
22 relative to the blade 24 from the open position towards the
closed position. An advantage of the present invention is that the
shears 20 appear, and operate in a manner, very similar to
conventional manually powered scissors. This conventional type of
operation is advantageous because little or no training or
adaptation to the power operated shears 20 is required.
[0052] The blades 22, 24 are supported in a frame 62 about an axis
AA. The frame 62 supports the blade 24 in a fixed relative
position. The blade 22 is pivotable relative to the frame 62 and
relative to the fixed blade 24 about the axis AA. A thumb handle
portion 64 is formed in the frame 62 for receiving an operator's
thumb to support and control the shears 20. A finger loop handle 66
is supported in the frame 62 for pivotal movement. Thus, the blades
22, 24 and the finger loop handle 66 are all supported on the frame
62 along the axis AA. In response to pivotal movement of the handle
66 relative to the frame 62 and thumb handle portion 64, the blade
22 is power driven to pivot relative to the blade 24.
[0053] The frame 62 also supports a servo mechanism 82 (FIGS. 1-5)
for controlling the power applied to pivot the blade 22. The servo
mechanism 82 includes a servo control valve 84 (FIG. 3), an
optional safety valve 86, an actuator 88, a drive link 102, and a
feedback linkage 104. The drive link 102 transmits power from the
actuator 88 to the pivotable blade 22. The feedback linkage 104
determines the difference between the position of the finger loop
handle 66 relative to the frame 62 and the position of the pivotal
blade 22 relative to the frame. The feedback linkage 104
communicates the difference between the position of the blade 22
and the position of the loop handle 66 to the servo control valve
84. The control valve 84 selectively permits or inhibits the flow
of a power medium to the actuator 88. The power is preferably
provided by a fluid, such as pressurized air. However, it will be
apparent that hydraulic or electrical power assist can be used.
[0054] Another mounting arrangement between a modified fixed blade
24B and a modified frame 62B is illustrated in FIG. 19. The
mounting arrangement between replaceable blades 22B, 24B and the
frame 62B is designed to be secure and reliable, yet easily
replaceable, when the blades are to be changed. The modified frame
62B includes a pair of load bearing pins 63 fixed to and extending
transversely from a portion of the frame 62B. The pins 63 are
located on substantially diametrically opposite sides of the axis
AA about which the blades relatively pivot. The fixed blade 24B
includes a pair of openings 67A, 67B formed in its mounting portion
290B. The load bearing pins 63 are received in the pair of openings
and receive the majority of the load between the frame and the
blades occurring during relative pivoting of the blades 22B, 24B
during a cutting operation.
[0055] Construction
[0056] The pivotable blade 22 is preferably formed from a suitable
metal, such as stainless steel. The cutting edge 42 is formed in
the blade 22 by a suitable operation such as by grinding and/or
polishing. Preferably, the cutting edge 42 is substantially
straight. However, it will be apparent that the cutting edge 42 may
be formed into any suitable shape necessary to perform a desired
cutting function, for example, a large radius curve or straight
portion and a curved tip end portion with a relatively large
radius.
[0057] The frame 62 (FIGS. 8 and 9) supports all of the parts of
the shears 20. The thumb handle portion 64 is integrally formed in
the frame 62 for receiving an operator's thumb. The frame 62 also
includes a recess 120 (FIG. 8), a recess 122 (FIGS. 6 and 9),
exhaust port 129 (FIG. 9), an actuator support 124 (FIGS. 8 and 9),
valve chambers 126, 128 (FIG. 9), a thumb opening 142 and an
attachment hook 144. The attachment hook 144 permits the frame 62
and shears 20 to be connected during use to a weight compensating
device, such as a constant force spring. The recess 120 (FIG. 8) in
the frame 62 receives the feedback linkage 104 and a pivot portion
of the finger loop handle 66. A support 118 is integrally formed on
the frame 62 and projects generally perpendicularly from a side
surface 116 defining a portion of the recess 120, The support 118
is received in an opening 119 (FIG. 14) in the pivot portion of the
finger loop handle 66 in a close fit relationship for pivotal
movement about the axis AA. The uncovered recess 120 allows easy
removal of any debris that may enter the recess and contact the
feedback linkage 104 or pivot portion of the finger loop handle 66.
A return spring 226 (FIG. 14) is located within the recess 120 and
engages both the finger loop handle 66 and the frame 62. The return
spring 226 continually biases the loop handle 66 towards a fully
open position, as illustrated in FIG. 2.
[0058] A recess portion 130 (FIG. 8) defines a space which is in
communication with the recess 120 and the recess 122 to permit
interaction between the blades 22, 24; the finger loop handle 66;
the servo mechanism 82 and the feedback linkage 104. The recess
portion 130 is located between the recess 120 and thumb handle
portion 64. The recess 130 receives the drive link 102 (FIGS. 4 and
5) therein, The drive link 102 is supported for pivotal movement
within the recess portion 130 at openings 132 (FIGS. 8 and 9) by a
pin 134 (FIG. 14). extending through the opening. The drive link
102 (FIGS. 4 and 5) connects the actuator with the pivotable blade
22. The drive link 102 forces the blade 22 to pivot relative to the
frame 62 and relative to the fixed blade 24 in response to movement
of the rod 166 (FIG. 14) of a part in the actuator 88.
[0059] The recess 122 in the frame 62 receives the blades 22, 24. A
cavity 146 (FIGS. 6 and 9) within the recess 122 extends coaxially
inside of the support 118 which projects to the recess 120 from the
surface 116. The opening 146 receives a support member 148 on which
the blades 22, 24 are supported. The blade 22 is closely fit about
the support member 148 for pivotal movement about the axis AA, The
blade 24 is also closely fit on the support member 148. The blade
24 is fixed relative to the frame 62 by a surface 150 of the blade
that engages surfaces 152, 154 of the recess 122, which prevents
movement of the blade relative to the frame 62. The surfaces 152,
154 in the recess 122 are located on diametrically opposite sides
of the blade 24 relative to the axis AA to engage the surfaces 150
and 150B of a mounting portion 290 (FIG. 11) of the fixed blade 24
in connection with the support member 148 to accommodate reaction
forces acting on the blade 24. The blades 22, 24 are illustrated in
the fully open position in FIGS. 2 and 7. The pivotable blade 22 is
disposed at an acute angle W of about 40.degree. to 45.degree.
relative to the fixed blade 24. This angle W, however, can be
predetermined and varied for specific job requirements, such as by
using a different servo mechanism 82, blade 22 or frame 62.
[0060] The recess 122 is closed by a latch cover plate 162 (FIGS. 6
and 7), after the blades 22, 24 are received therein. The frame 62
and latch cover plate 162 protect the blades 22, 24 from debris
entering the recess 122. The latch cover plate 162 includes a body
portion 160 for closing the recess 122 and for preventing the
blades 22, 24 and support member 148 from movement laterally
outwardly of the recess in a direction along the axis AA.
[0061] It will be clear from FIG. 7 that, by virtue of the shape of
the opening in which the cover 162 fits and through which the
mounting portion 290 and actuating portion 246 must fit to be
installed or removed, the blades must be closed during installation
or removal to align the actuating portion with the opening. This
provides a safety feature to reduce risk of an operator being cut
by the sharp edges during handling or by having the blades in an
unsafe condition at the time they are installed and connected to
the actuating mechanism.
[0062] The latch cover plate 162 is movable relative to the frame
62 in the directions indicated by arrows 159 (FIG. 6) formed on the
exterior of the latch cover plate to permit access to the blades
22, 24. A connecting portion 157 extends from the body portion 160
to pivotally and slidably attach the latch cover plate 162 to the
frame 62. The connecting portion 157 has a slot 157S formed therein
for receiving a pin 157P. The slot 157S allows the latch plate
cover 162 to slide as well as pivot relative to the pin 157P. The
slot 157S has an hour-glass shape across its width so the walls
defining the slot are flexible to urge the latch plate cover 162 in
one of two directions it can slide to tend to retain the latch
plate cover in a closed or open position. The latch cover plate 162
is free to pivot outwardly of the frame 62 when the latch cover
plate is axially moved to an open position as indicated by open
arrow 159, by virtue of freeing retaining tabs 151, 153 from their
respective receiving slots 151S, 153S.
[0063] A finger grip 155 is provided on a body portion 160 to move
the latch cover plate 162 to an open position permitting access to
the recess 122 and blades 22, 24. Each retaining tab 151, 153
includes a ramp 151R, 153R which is received in a respective slot
151S, 153S in the frame 62. The ramps 151R, 153R are tapered to
permit relatively easy insertion of the tabs 151, 153 into a slot
151S, 153S and to force the latch cover plate 162 inwardly towards
the recess 122 in a direction along the axis AA. This assures that
the inwardly facing surface of the latch cover plate 162 engages a
bushing 149 on the support member 148 to prevent lateral movement
of the blades 22, 24 and support member 148 from the recess
122.
[0064] The actuator support 124 (FIG. 8) extends from the frame 62
and includes a pair of fingers 125 spaced apart forming a clevis.
The actuator support 124 pivotally receives a mounting portion 164
(FIG. 3) of the actuator 88 between the fingers 125. Thus, the
actuator 88 is pivotally fixed to the frame 62 at one end. The
actuator 88 includes a rod 166 (FIG. 14) extending therefrom in a
direction opposite to the mounting portion 164.
[0065] The rod 166 is fixed to a piston 168 (FIG. 17A) for
reciprocal movement within a cylindrical chamber 182 in the
actuator 88. The piston 168 divides the chamber 182 into a variable
volume "open" chamber 184 and a variable volume "cut" chamber 188.
When fluid flow under pressure is directed into the open chamber
184 through port 186 and fluid is permitted to exhaust from cut
chamber 188, the greater pressure within the open chamber forces
the piston 168 and rod 166 to move axially to the right in a blade
open direction, as viewed in FIG. 17A. The rod 166 moving in a
blade open direction, moves the blade 24, through the drive link
102, in a direction towards the fully open position, as illustrated
in FIG. 2. When fluid pressure is directed into the "cut" chamber
188 through port 190, and fluid exhausts from the cut chamber 184,
the piston 168 and rod 166 are forced to move to the left in a
blade cut direction, as viewed in FIG. 17A. The rod 166 moving in a
blade cut direction moves the blade 24, through the drive link 102,
towards the fully closed position, as illustrated in FIG. 1. The
actuator 88 is located relative to the frame 62 and sized to fit
comfortably within the palm of a hand of an operator of the shears
20. The actuator 88 provides sufficient force to cut items, such as
small chicken bones.
[0066] The servo control valve 84, (FIGS. 3, 16 and 17A-H) is
received in the valve chamber 128 which extends completely through
the frame 62. The servo control valve 84 is operably coupled to the
actuator 88 by fluid conducting lines 222, 224 (FIGS. 3, 4 and
17A). The lines 222, 224 may be located internal or external of the
frame 62. Preferably, the lines 222, 224 are external with the line
222 fitting in a groove in the thumb handle portion 64 facing away
from the blades 22, 24. The optional safety valve 86 is received in
the valve chamber 129 which extends only partially through the
frame 62.
[0067] An optional safety lever 202 (FIG. 5) is pivotally supported
in the thumb handle portion 64 of the frame 62 about a pin 204. A
button 206, at the end of one relatively long leg portion of the
safety lever 202, extends into the thumb opening 142 of the thumb
handle portion 64 under bias of the safety valve 86. When an
operator inserts a thumb into the thumb opening 142, the button 206
is depressed and the lever 202 pivots about the pin 204.
[0068] A relatively short end portion 208 of the lever 202 moves a
rod 210 (FIGS. 5 and 16) in the safety valve 86 to a position
permitting fluid pressure from a fluid inlet 211 to the servo
control valve 84 through a passage 212. When the button 206 is not
depressed, a check valve 216 in the safety valve 86 is biased by a
spring 217 to block the flow of pressurized fluid to the passage
212 and the servo control valve 84. This assures that fluid
pressure is applied to the actuator 88 to move the blade 24 only
when an operator has a thumb in the thumb opening 142 in the thumb
handle portion 64 of the frame and can control the shears 20. This
optional feature, although shown, is omitted in the preferred
embodiment to eliminate a risk that can occur in the event of an
interruption in power while the blades are in an open relationship.
Without power, the blades will remain open upon the moving of the
finger loop 66 to a closed position, which could occur through
carelessness or inadvertence, notwithstanding that the loop is
spring biased to an open position. In the event of such an
occurrence, if the safety lever 202 is operated when the power is
returned, the open blades will immediately snap shut, creating a
potential danger believed greater than that protected by the safety
lever.
[0069] A cutting or shearing action is effected during closure of
the blade 24 relative to the blade 22 from the position illustrated
in FIG. 2 to the position illustrated in FIG. 1. The blade 22 is
pivotable relative to the frame 62 about the member 148 and the
axis AA. The blade 22 is pivotable in response to movement of the
loop handle 66 relative to the frame 62. When the shears 20 are in
the fully closed position, as illustrated in FIG. 1, the blades 22,
24 overlie one another in a side-by-side engaged relationship.
[0070] The pivotable blade 22 is illustrated in FIG. 10 in detail.
The pivotable blade 22 includes an opening 242 extending through
the blade and sized to closely fit over the member 149. The
pivotable blade 22 includes a relatively long cutting portion 244
extending from the opening 242 and having the cutting edge 42
formed thereon. The pivotable blade 22 includes an actuating
portion 246 extending from the opening 242 in a direction away from
the cutting portion 244, at an obtuse angle B relative to a
straight unground edge portion 247 located directly below the
opening 242 and contiguous with the cutting edge 42. The obtuse
angle B is in the range of 120.degree. to 170.degree., and is
preferably 144.degree..
[0071] The extent E1 of the actuating portion 246 from the center
of the opening 242 is less than the extent E2 of the cutting
portion 244 from the center of the opening. The ratio of the extent
E2 of the cutting portion 244 to the extent E1 of the actuating
portion 246 is in the range of between one to one (1:1) to ten to
one (10:1), and preferably is 4.9:1. The extent E2 of the cutting
portion 244 is preferably 5 inches from the center of the opening
242 to the tip of the blade. The extent E1 is preferably 1.006
inches from the center of the opening 242 to an end surface 249 of
the actuating portion.
[0072] The actuating portion 246 of the blade 22 includes an
elongated slot 248 opening through the end surface 249 and
extending in a direction toward the opening 242. The slot 248 is
defined by two parallel side surfaces 250, 252 extending in a
direction substantially parallel to a line extending from the
center of the opening 242 at an angle of 144.degree. relative to
the unground edge portion 247. The actuating portion 246 also has a
pair of substantially parallel extending surfaces 254, 256
extending in a direction parallel to the slot 248 defining side
surfaces 250, 252 of the actuating portion. The slot 248 accepts a
driving member 258 (FIGS. 14 and 15) of the drive link 102 to force
the blade 22 to pivot relative to the fixed blade 24 upon pivoting
of the drive link. A heel 284 is located on the actuating portion
246 opposite the opening 242 from the cutting portion 244. The heel
284 includes a ride surface 288 on the blade 22. The fixed blade 24
is illustrated in detail in FIGS. 11-13. The fixed blade 24
includes an opening 280, a cutting portion 282 and a mounting end
290. The opening 280 is formed to closely receive a portion of the
support member 148 and 149. The support member 148, blade surfaces
150 and 150B and frame surfaces 152, 154 cooperate to prevent
movement of the blade 24 relative to the frame 62 (FIG. 6). The
cutting edge 44 of the fixed blade 24 is formed in the cutting
portion 282 by grinding and/or polishing. The cutting edge 44 has a
straight portion adjacent the mounting end 290 and a distal end
portion having a slight curvature; for example, a radius in the
range of 30-200 inches. The cutting portions 244, 282 of the
respective blades 22, 24 are slightly bowed away from one another
between their tips and respective openings 242, 280. An alternative
fixed blade 24A (FIG. 11A) includes a ball tip 286 at the end of
cutting portion 282A, which aids in eviscerating animal
carcasses.
[0073] The mounting end 290 (FIGS. 12 and 13) of the fixed blade 24
is located relative to the opening 280 diametrically opposite to
the cutting portion 282. The mounting end 290 has a portion 287
bent upwardly, as viewed in FIGS. 12 and 13, during manufacture of
the blade 24 away from a lower side surface 292 of the blade, as
viewed in FIGS. 12 and 13. This deformed portion 287 of the
mounting end 290 assures that the bent portion 287 extends in a
direction parallel to the upper side surface 294, but offset. The
bent portion 287 of mounting end portion 290 preferably extends
0.010 inch from the upper side surface 294 of the blade 24. The
bent portion 287 of mounting end 290 is preferably ground flat
after the deforming operation in order to form a surface generally
parallel with the upper side surface 294 of the blade 24.
[0074] An alternate mounting end 290A (FIG. 13A) of the fixed blade
24A (FIG. 11A) is located relative to the opening 280 diametrically
opposite to the cutting portion 282. The mounting end 290A has a
portion 287A deformed upwardly, as viewed in FIG. 13A, during
manufacture of the blade 24A away from a upper side surface 294 of
the blade, as viewed in FIG. 13. This deformed portion 287A of the
mounting end 290A is formed by engaging a lower side surface 292A
extending in a direction parallel to the upper side surface 294A
with a punch to form recess 289. The deformed portion 287A of
mounting end portion 290A is forced by the punch and preferably
extends 0;010 inch from the upper side surface 294A of the blade
24A. The deformed portion 287A of mounting end 290A is preferably
ground flat after the deforming operation in order to form a
surface generally parallel with the upper side surface 294A of the
blade 24A,
[0075] The ride surface 288 (FIG. 10) of the pivotable blade can be
interchanged with either raised surface 287 or 287A (FIGS. 13 &
13A) of the fixed blade, as preferred to suit the manufacturing
process. These are mating features which cooperate to bias the
cutting edges of the blades together.
[0076] The cutting edges 42, 44 are adapted to face one another
when the blades are properly installed in the frame 62. When the
blades 22, 24 are relatively pivoted towards one another, the
deformed portion 287 of the mounting end 290 of the fixed blade 4
engages the ride surface 288 in the heel 284 of the pivotable blade
22. The engagement between the deformed portion 287 and the ride
surface 288 assures that the cutting edges 42, 44 are continuously
biased towards one another to contact and to create a moving
cutting point during closure of the blade 22 relative to the blade
24.
[0077] Another mounting arrangement between a modified fixed blade
24B and a modified frame 62B of the shears 20B is illustrated in
FIGS. 19, 20 and 26. The mounting arrangement between replaceable
blades 22B, 24B and the frame 62B is secure and reliable, yet
facilitates easy replacement, when the blades are to be
changed.
[0078] The modified frame 62B has a thumb recess 64B rather than a
complete encirclement for the thumb, and employs a strap 62C that
extends across the back of the hand of an operator. Also, the
safety valve 86 is omitted and a passage 86A extends within the
frame, communicating with a cross passage 212B through which fluid
under operating pressure is supplied directly to the servo valve
84. The mechanism for operating the blades is otherwise the same as
described with respect to the embodiment utilizing the frame
62.
[0079] The modified frame 62B includes a pair of load bearing pins
63 fixed to and extending transversely from a cavity portion 65 of
the frame. The load to bearing pins 63 are located on substantially
diametrical opposite sides of the axis AA about which the blade 22B
pivots, offset only slightly as indicated at Q1 at FIG. 19 for
structural convenience from a precise diametrically opposite
relationship. The fixed blade 24B includes a mounting portion 290B
that has a substantially planar surface 291 (FIG. 20). The fixed
blade 24B includes a pair of openings 67A, 67B formed in its
mounting portion 290B. One opening 67A is substantially circular
and tightly fits about the exterior of one pin 63. The other
opening 67B is elongated into a generally oval or elliptical shape
with a width that tightly fits about the other pin 63 and a length
that is greater than the diameter of the pin. This elongated
opening 67B allows for some manufacturing tolerances in the
placement of the openings and/or the pins 63. The wide spacing of
the pins 63 and the openings 67A, 67B and their relationship to the
pivot axis AA and their fit with the pins 63, results in effective
anchoring of the blades and prevents movement of the fixed blade
22B.
[0080] The load bearing pins 63 withstand the majority of the load
applied between the blades and frame during operation of the blades
22B, 24B as these blades act against a workpiece. The widely spaced
pins 63, acting as a couple, bear the shearing load between the
blades, and avoid the use of a relatively small edge surface of a
blade to engage a part of the frame 62B to absorb such load.
[0081] The replaceability and interchangeability of the blades 22B,
24B or other working members as an assembled unit is an important
feature of the shears or tool of the present invention. For
example, a straight blade assembly is illustrated in FIG. 20. The
blades 22B, 24B each have a cutting edge 42B, 44B that is
essentially straight along its entire length of approximately 4.00
inches to 4.50 inches. When the cutting edges 42B, 44B of these
blades 22B, 24B wear, become dull, otherwise damaged or when the
type of blade is required to be changed, they can easily be
replaced by closing the blades, loosening a blade screw 292 (FIG.
20) that extends along the axis AA and which connects the blades to
a threaded opening 293 in the frame 62B and removing the blades as
a unit by lifting them off of the pins 63.
[0082] For safety, the removal or replacement of the blades 22B,
24B requires that the blades be in a closed position relative to
one another. To insure that the blades 22B, 24B are closed during
removal or installation, a portion 297, crescent shaped in the
embodiment shown, forms a part of the actuating portion 264B of the
pivotable blade 22B. When the pivotable blade 22B of an installed
pair is in a position other than the relatively closed position,
this crescent shaped portion 297 will be located in an open area of
the frame 62B, indicated at 298 (FIG. 20), behind and below a frame
portion 299 that interferes with installation and removal of the
blades in other than a closed condition. This will be clear from
FIG. 19. The pivotable blade 22B must be in its closed position
relative to the fixed blade 24B for the crescent shaped portion 297
to be located out of the area 298 formed in the modified frame 62B.
This relative location of the crescent shaped portion 297 out of
the slot 298 permits the movement of the blades in a direction
parallel to the extent of the pins 63. A replacement set of blades
22B, 24B can then be installed or the blades can be serviced or
sharpened and then reinstalled.
[0083] The blades 22B, 24B are fastened together as a unit by a
pivoting assembly (FIG. 20A) which includes a lock nut 294, blade
washer 295, pivot nut 296 and the blade screw 292. The lock nut 294
and pivot nut 296 interengage along a threaded portion 294A to
maintain the blades 22B, 24B together while also permitting pivotal
action relative therebetween. The blade screw 292 extends through
both the lock nut 294 and pivot nut 296. A threaded portion 292A is
received in the opening 293 to maintain the blades 22B, 24B in the
frame 62B and on the pins 63. A smaller diameter nonthreaded
portion 292B is located within the lock nut 294 and pivot nut 296
to allow the screw to move freely while engaging or disengaging the
thread portion of the Frame 293. This feature allows the screw to
remain captured within the blade set when the set is removed from
the frame, pivoting of the blade 22B. The pivot nut 296 has a "D"
shaped boss 296P on its exterior portion to fit within a "D" shaped
opening 296D the fixed blade 24B to prevent relative rotation
between the pivot nut and the fixed blade 24B.
[0084] The replaceable blade unit includes the straight blade
assembly illustrated in FIGS. 19A and 20, which has relatively
straight cutting edges 42B, 44B and a relatively blunt end 299B on
the fixed blade 24B. The pivotable blade has a curved end portion
with a pointed end 299P (See FIG. 20) The cutting edges 42B, 44B
cooperate to shear a workpiece by engaging along a line of contact
that is contained in a plane extending substantially parallel to
the planar surface 291.
[0085] As illustrated in FIGS. 21 and 21A a modified version of the
replaceable blade unit is illustrated. The blade unit includes a
pivotable blade 22C with a pointed end 299CP. A fixed blade 24C has
a blunt end 299CB. The blades 22C, 24C engage along a path curved
relative to the planar surface 291C of the fixed blade 24C, as
illustrated in FIG. 21A. This curvature can be "right hand" as
shown, or opposite (not shown).
[0086] As illustrated in FIG. 22, another replacement blade unit
includes a fixed blade 24D having a ball tip 299BT. The ball tip
299BT permits the fixed blade 24D to be inserted into a narrow
channel in the workpiece without cutting or digging into the
surface. A pivotable blade 22D includes a relatively sharp pointed
end 299PE which can be used to puncture a product or workpiece.
[0087] A replaceable blade unit illustrated in FIG. 23 is
designated a "gizzard" blade assembly. The fixed blade 24G has a
relatively sharp pointed end 299GB to impale a product or
workpiece. The pivotable blade 22G has a squared end 299GS. As
illustrated in FIG. 24 a replaceable blade unit is a straight short
blade assembly. The blades 22F, 24F are relatively shorter than the
blades 22B, 24B illustrated in FIG. 20. The fixed blade 24F has a
raised blunt end 299BE. A replaceable blade unit illustrated in
FIG. 25 is described as a "neck breaker" blade assembly, The blades
22B, 24B are relatively thick, taken in the direction of relative
pivotal movement and, thus, are relatively strong in that
direction. These blades are typically used for breaking bones in a
poultry workpiece such as a chicken or turkey. The neck breaker
blade assembly has its pivotal blade 22G with a removable anvil
edge 22AE. The anvil edge 22AE is relatively wide, taken in a
direction normal to the direction of relative pivotal movement.
This blade 22G cuts by forcing the work product against and into a
sharp edge 245E of the fixed blades 24G as the blunt anvil cutting
edge and the sharp cutting edge are brought into mutual contact
crushing when the moveable anvil edge 22AE is brought into
engagement with a sharp edge 24SE of the fixed blade 24G. Such a
forceful engagement between the two blades can also be used by
other working members such as a power operated crimping tool with
suitable crimping edges.
[0088] The drive link 102 is a bell crank member having a general
L-shape. As illustrated in FIGS. 14 and 15, the drive link 102 is
connected for pivotable movement about the pin 134. The pin 134 is
received in the openings of the frame 62 and is located
approximately along the longitudinal center line of the fixed blade
24. The drive link 102 pivots in the frame 62 at a location between
the rod 166 of the actuator 88 and the slot 248 of the pivotable
blade 22. A relatively longer leg 302 of the drive link 102 is
connected with the rod 166 by a pin 306. The distance between the
centers of the pins 134 and 306 is preferably 1.24 inches, The
relatively shorter leg 304 of the drive link 102 is connected with
the actuating portion 246 of the pivotable blade 22. The linkage
between the leg 304 and the slot 248 of the pivotable blade 22 is
through the pin and roller 258, which is in rolling engagement with
the blade. The distance between the centers of the pins 258 and 134
is preferably 0.83 inch.
[0089] The ratio of the distances of the longer leg portion 302 to
the shorter leg portion 304 is in the range of 1.15:1 to 1.85:1 and
is preferably about 1.50:1. This "leg ratio" being greater than 1.0
provides an increase in force transmitted to the actuating portion
246 of the blade 22 compared to the force applied to the drive link
102 by the rod 166. This force multiplication due to the mechanical
advantage provided by the drive link 102 enables a relatively large
cutting force to be applied between the blades 22, 24,
Concurrently, a decrease in angular travel of the blade 22 compared
between the angle of travel of the long leg 302 occurs as the blade
is closing. The decreasing angular travel produces a
proportionately increasing amount of force applied to blade 22,
which compensates in part for the drop in cutting force that occurs
as the cut point moves toward the end of the blade.
[0090] Pivotable movement of the drive link 102 about the pin 134
pivots the blade 22 about axis AA through engagement of the blade
by the pin 258 in the slot 248. For example, when the rod 166 of
actuator 88 is forced to move axially to the left, as viewed in
FIG. 15, the longer leg portion 302 of the drive link 102 pivots
clockwise about the pin 134 causing the leg portion 304 to follow
with clockwise pivotal movement about the pin. However, the arcuate
movement at pin 258 is less than the arcuate movement at pin 306.
This results because the distance from the centers of pin 134 to
pin 258 is less than the distance from the centers of pin 134 to
the center of pin 306. To accommodate the pivoting of the blade 22
and the link 102, while keeping the construction compact, the slot
248 begins at least within 0.55 inch from the axis AA and extends a
distance of at least 1.0 inch from the axis AA.
[0091] The finger loop handle 66 is received in the recess 120 in
the frame 62. The finger loop handle 66 pivots relative to the
support 118 about the same axis AA as the blade 24 pivots. The
finger loop handle 66 pivots about 20.degree. to 25.degree.
relative to the frame 62 between the fully open position
illustrated in FIG. 2, and the fully closed position illustrated in
FIG. 1, or about half of the arcuate movement of the pivotable
blade 22. The finger loop handle 66 includes a finger handle
portion 322 for receiving therein up to four fingers of an
operator's hand located opposite the thumb. The finger handle
portion 322 is preferably continuous and closed which allows an
operator's fingers to move the loop handle 66 in both directions
for pivotable movement about the support 118, and also acts as a
guard for the fingers.
[0092] A pivot portion 320 of the loop handle 66 surrounds the
support 118 and is narrower than the width of the finger handle
portion 322. The return spring 226 engages an end surface 326 on
pivot portion 320 of the finger loop handle 66 to continuously bias
the finger loop handle portion 322 towards the fully open position,
as illustrated in FIG. 2.
[0093] A blade link 340 (FIG. 14) forms a part of the feedback
linkage 104. The blade link 340 is also received on the support
member 118 at opening 338 for pivotable movement about the axis AA.
The blade link 340 is located in the recess 120 of the frame 62.
The blade link 340 is axially offset from the pivot portion 320 of
the loop handle 66.
[0094] The blade link 340 detects movement of the pivotable blade
22 and communicates that movement to a difference link 362 in the
feedback linkage 104. The blade link 340 detects movement of the
pivotable blade 22 at one end by engagement with the pin 258 in the
drive link 102 that extends through a slot 342 of the blade link.
The movement of the blade link 340 is transmitted to the difference
link 362 through a pin 344 at a location relative to the opening
338 which is generally opposite the slot 342. The distance from the
axis AA at which the pin 258 engages a surface defining the slot
342 of the blade link 340 is in the range of 0.73 to 0.96 inch. The
distance to the center of the pin 344 from the axis AA is 0.46
inch. The pin 258, thus, moves through an arcuate distance greater
than the arcuate distance that the pin 344 moves and is
proportionately greater by a ratio in the range of about 1.5:1 to
about 2.1:1.
[0095] The difference link 362 is connected between the pin 344 of
the blade link 340 and a pin 366 on the finger loop handle 66. The
difference link 362 forms part of the feedback linkage 104 and
communicates a difference between pivotal movement of the blade 24
and the pivotal movement of the finger loop handle 66 to the servo
control valve 84.
[0096] The difference link 362 is a generally L-shaped member
formed by legs 374, 376 meeting at an apex. A pin 382 in an
aperture 370 at the apex communicates movement of the apex to an
actuator link 386 of the servo valve 84. The difference link 362
includes a slot 364 in leg 374 for receiving the pin 344 of the
blade link 340 and an opening 368 in the leg 376 for receiving the
pin 366 of the finger loop handle 66. The distance from the center
of the opening 368 in one leg 376 of the difference link 362 to the
center of the aperture 370 at the apex is shorter than the distance
between the center of the aperture 370 to the average center of the
slot 364 in the other leg 374. The difference link 362 has a ratio
of the length of leg 374 to the length of leg 376 in the range of
about 1.3:1 to 1.7:1. Thus, a relatively larger proportion of
movement of the finger loop handle 66 is communicated to the servo
control valve 84 than the proportion of movement of the pivotable
blade 22.
[0097] The offset distance of the aperture 370 from a line from the
centers of openings 368 and slot 364 on link 362 results in a
decrease in speed of movement as the blade 22 nears the closed
position. This decrease in speed of movement of the blade 22
relative to the movement of the handle 66 is represented by curve
300 in FIG. 18 as "blade gain ratio." The blade gain ratio is
plotted as a function of the angle between the blades 22, 24. This
noticeable gain ratio means that the change in angle between the
blades 22, 24, to the change in angle between the handle 66 and the
frame 62, decreases from over a 6:1 ratio at the fully open
position to about 1:1 at the closed position. This is compared to
the constant 1:1 ratio of conventional scissors in curve 310. The
variable "blade gain ratio" is particularly advantageous for
controlling cutting with a relatively slow closure rate near the
fully closed blade position.
[0098] A pin 382 received in the aperture 370 at the apex of the
difference link 362 extends into an opening 384 of the actuator
link 386. The actuator link 386 includes an opening 388 at an end
opposite to the opening 384. The opening 388 receives a pin 390
that is connected with a stem 400 in the servo control valve
84.
[0099] The actuator link 386 transmits motion of the difference
link 362 to the stem 400 in the servo control valve 84. Because the
difference link 362 reflects the difference in pivotal movement
between the loop handle 66 and the pivotable blade 22 and moves the
actuator link 386 and, hence, the stem 400 in the servo control
valve 84, it provides a difference feedback signal to the servo
control valve.
[0100] For example, the finger loop handle 66 is pivoted by an
operator from the open position to the closed position nearer the
frame 62 when the blades 22, 24 are in the fully open position, as
illustrated in FIG. 2. The difference link 362 then pivots
clockwise about the pin 344 by the pin 366 in the finger loop
handle 66. The pin 382 forces the actuator link 386 to move the
stem 400 axially inward within the servo control valve 84, in a
direction that causes the pivotable blade 22 to move towards the
closed position. There is a time lag before the piston 168 and the
power rod 166 of the actuator 88 force the pivotable blade 22 to
pivot towards the closed position that is illustrated in FIG. 1.
During this time lag, until the blade 22 begins to pivot, the
difference link 362 has pivoted only about the pin 344 supported in
the blade link 340. Once the blade 22 begins to pivot, the position
of the difference link 362 then reflects a tendency to pivot about
pin 366. If the finger loop handle 66 continues to move ahead of
the blade 22 movement, then movement of pins 366, 344 tend to
cancel their influence on the difference link 362 and produce an
apparent rotation about pin 382. The actuator link 386 essentially
maintains its position and the blade 22 continues to pivot. If the
blade 22 movement tends to catch up to the finger loop handle 66
movement, the difference link 362 pivots about pin 366, causing the
actuator link 386 to move the stem 400 in a direction axially out
of the valve 84, reducing the flow of fluid to the actuator 88 and,
hence, showing or stopping pivoting of the blade 22.
[0101] Thus, the servo control valve 84 is actuated from the
position illustrated in FIG. 17A through the position illustrated
in FIGS. 17B through 17D by movement of the difference link 362.
The travel limit of the stem 400 within the servo control valve 84
is illustrated in FIG. 17D. During the axial inward movement or cut
signal, indicated by the arrow 396 (FIG. 16), of the stem 400
within the servo control valve 84, fluid is directed to the line
222 to the port 190 and into the "cut" chamber 188 in the actuator
88. This forces the piston 168 and its associated rod 166 to move
in a cut direction and move the blade 22 from the open position
towards the closed position. The rod 166 forces the drive link 102
to pivot the pivotable blade 22 toward the fixed blade 24 with a
cutting action.
[0102] During this pivotable movement of the pivotable blade 22
towards the fixed blade 22, the blade link 340 communicates the
movement of the pivotable blade to the difference link 362. The
difference link 362 pivots about the pin 366 in a clockwise
direction which causes the actuator link 386 to pull the stem 400
in a direction axially outward of the servo control valve 84. The
pivotable blade 22 tries to catch up to the desired position
indicated by the position of the finger loop handle 66 relative to
the frame 62. The difference link 362 continues to pivot clockwise
about the pin 366. The pivotable blade 22 does eventually catch up
to the desired blade position indicated by the position of the loop
handle 66 relative to the frame 62.
[0103] The difference link 362 detects that the position of the
pivotable blade 22 relative to the blade 24 or frame 62 has caught
up to the desired position indicated by the position of the loop
handle 66 relative to the frame 62. The difference link 362 stops
rotating about either pin 366 or 344. No motion is, thus, imparted
to the actuator link 386 and the stem 400 is in a "neutral"
position, illustrated in FIG. 17G, which does not cause any further
pivoting of the blade 22 from the position it was in when the stem
reached the neutral position. It will be apparent that from the
position that the blade 22 stopped, it could thereafter be opened,
closed or could remain stationary relative to the blade 24, as long
as the blade 22 is between the fully open or fully closed positions
when it stopped moving.
[0104] To move the blade 22 towards the open position of FIG. 2,
the reverse takes place. The loop handle 66 is pivoted away from
the frame 62 towards the fully open position illustrated in FIG. 2.
This forces the pin 366 to pivot the difference link 362 at opening
368 counterclockwise about the pin 344. This pivoting motion of the
difference link 362 imparts a force to the actuator link 386 that
pulls the control stem 400 in a direction axially outward of the
servo control valve 84 towards the position illustrated in FIG.
17H.
[0105] Such axially outward motion causes fluid to flow through
line 224 to port 186 and into open chamber 184. Fluid pressure
forces the piston 168 and rod 166 to move in a direction towards
the mounting portion end 164 of the, actuator 88. This axially
inward movement of the rod 166 in the actuator 88 causes the drive
link 102 to pivot in a clockwise direction about the pin 134 which
causes the actuating portion 246 of the blade 22 to pivot about the
axis AA in a counter-clockwise direction. Pivoting of the drive
link 102 in a clockwise direction causes the blade 22 to move from
the closed position illustrated in FIG. 1 relative to the fixed
blade 24 toward the open position illustrated in FIG. 2.
[0106] Thus, the stem 400 moves from the position in the servo
control valve 84 illustrated in FIG. 17G progressively to the
position illustrated in FIG. 17H. The position illustrated in FIG.
17H is a reversing travel position or a position in which opening
motion of the blade 22 will occur.
[0107] The servo control valve 84 (FIG. 16) controls fluid flow to
the actuator 88. The servo control valve 84 includes a valve body
422 that defines an elongated chamber 424. Two oppositely facing
pistons 426, 428 are independently movable longitudinally within
the chamber 424 of the valve body 422. Each piston 426, 428 has an
inner annular first valve seat 442 and an outer annular first
obturating surface 444. A reciprocable valve stem 446 extends
through and is at least partially surrounded by the pistons 426,
428. The valve stem 446 is connected to and is part of stem 400.
Each of the pistons 426, 428 includes a surface 447 for
transmitting force to the piston in a direction away from the
other. The servo control valve 84 may optionally include a
compression spring 445 between and acting concurrently against the
force transmitting surface 447 associated with each piston 426,
428.
[0108] Two oppositely facing spaced annular second obturating
surfaces 448 are carried by the valve stem 446 at opposite ends a
fixed distance D1 apart. The pistons 426, 428 are located between
the two second obturating surfaces 448 and are reciprocable
relative to the valve stem 446. Each of the second obturating
surfaces 448 are arranged to cooperate with one of the inner
annular first valve seats 442 to control fluid flow along the valve
stem 446 from the fluid inlet 212 intermediate the pistons 426,
428.
[0109] Two annular second valve seats 462 are fixed in the valve
body 422. Each of the second valve seats 462 is located to coact
with the outer annular first obturating surfaces 444 of one of the
pistons 426, 428. This contact limits the longitudinal movement of
the pistons 426, 428 in a direction away from each other and
controls fluid flow past the outer annular first obturating
surfaces 444.
[0110] A first port 482 to the chamber 424 is located between the
pistons 426, 428 and serves as a fluid inlet to the chamber. A
second port 484 and a third port 486 are for separate fluid
communication with the chambers 184, 188 through lines 222, 224,
respectively. The second port 484 and the third port 486
communicate independently with a common passage 488 in the frame 62
for exhausting fluid from the servo control valve 84 and shears 20
at exhaust port 129. The second port 484 and third port 486 are
associated with a respective one of the second valve seats 462 for
exhausting fluid from the chambers 184, 188. The second port 484 is
closable by the right piston 426, as viewed in FIG. 16, to block
fluid flow from the chamber 188 to the common passage 488. The
third port 486 is closable by the left piston 428, as viewed in
FIG. 16, to block fluid flow from the chamber 184 to the common
passage 488.
[0111] A fourth port 502 and a fifth port 504 to the chamber 424
are each located longitudinally outward of the pistons 426, 428 and
their associated second valve seats 462. The fourth port 502 is for
supplying fluid to and receiving fluid from the "cut" chamber 188
of the fluid actuator 88. The fifth port 504 is for supplying fluid
to and receiving fluid from the "open" chamber 184 of the fluid
actuator 88. The distance D1 between the two second obturating
surfaces 448 and the distance D2 between the two annular second
valve seats 462 are such that the pistons 426, 428 permit limited
fluid flow or a "controlled leakage" from the first port 482
equally to the fourth port 502 and fifth port 504 when the valve
stem 446 is in the "neutral" or first position. The distances D1
and D2 are also such that the pistons 426, 428 allow preferential
fluid flow through the fourth port 502 or the fifth port 504 and
only one of the second port 484 and the third port 486 when the
valve stem 446 is in a position other than the first position. It
should be apparent that the distances D1 and D2 may be established
so that the pistons 426, 428 completely block fluid flow to the
fourth port 502 and the fifth port 504 when the valve stem 446 is
in the first position.
[0112] Operation
[0113] The description will relate to the shears 20 and blades 22,
24 but is equally applicable to the use of the shears 20B, modified
frame 62B and blades 22B, 24B, and any other of the blades or work
members operable by the disclosed mechanism, To operate the shears
20 embodying the present invention the following procedure is
followed. Assuming that the operator desires to cut something, such
as cloth, paper, cardboard or meat, the shears 20 will normally
start with the blades 22, 24 in the fully open relative position
illustrated in FIG. 2. To move the blades 22, 24 from the open
position illustrated in FIG. 2 to the closed ending position
illustrated in FIG. 1, the operator first inserts a thumb into the
thumb opening 142 in the thumb handle portion 64 in the frame 62.
As the operator's thumb is fitted in the opening 64, the safety
button 206 if provided, is depressed to permit pressurized fluid to
pass through the safety valve 86 and into the servo control valve
84. In the preferred embodiment, the button, safety lever 202 and
safety valve 86 are omitted and pressurized fluid passes directly
to the control valve 84. At least one of the operator's fingers is
received in the finger handle portion 322 in the finger loop handle
66. The operator then manually pivots the finger loop handle 66
from the open position illustrated in FIG, 2 towards the closed
position illustrated in FIG. 1. The operator may stop the pivoting
movement of the finger loop handle 66 anywhere between the open and
closed position or continue to the travel limit or closed position,
illustrated in FIG. 1.
[0114] This starting of relative pivoting action of the finger loop
handle 66 forces the difference link 362 to pivot about the pin 344
in a clockwise direction (FIG. 14) and forces the actuator link 382
to move the stem 400 axially inward of the servo control valve 84
from the position illustrated in FIG. 17A to the position
illustrated in FIG. 17B. This motion of the stem 400 allows fluid
to flow to "cut" chamber 188 of the actuator 88 through port 502
which moves the piston 168 in a direction to move the rod 166
axially outward of the actuator. That is, the conical surface 448
disengages from the valve seat 442 on piston 426 to communicate the
first port 482 with the fourth port 502 to allow fluid flow to the
"cut" chamber 188. Concurrently, the left port 504 fluidly
communicates with the third port 486 to exhaust fluid from the
"open" chamber 184. The second port 484 is maintained blocked by
piston 426. Thus, the drive link 102 pivots counterclockwise about
the pin 134 and drives the pivotable blade 22 towards the fixed
blade 24.
[0115] Upon further pivoting movement of the finger loop handle 66
relative to the frame 62, but before the blade 24 catches up to the
position indicated by the finger loop handle, the difference link
362 pivots further about the pin 344 in a clockwise direction. This
causes the stem 400 to be moved farther inward of the servo control
valve 84 from the position illustrated in FIG. 17B to the position
illustrated in FIG. 17C. The conical surface 448 is spaced further
from the valve seat 442 on piston 426 and the piston 428 is spaced
further from annular valve seat 462, than the position illustrated
in FIG. 17B. This allows relatively more fluid flow between the
first port 482 and the fourth port 502 and between the fifth port
504 and third port 486. The greater fluid flow to the cut chamber
188 of the actuator 88 forces the piston 168 and rod 166 to pivot
the blade 22 even faster towards the closed position.
[0116] The maximum cut position of the servo control valve 84 is
illustrated in FIG. 17D. This position is reached by pivoting the
finger loop handle 66 quickly towards the frame 62 while cutting a
tough object. The difference link 362 pivots clockwise about the
pin 344 to move the stem 400 to its axial inward limit. The conical
surface 448 is spaced a maximum distance from the seat 442 of the
piston 426 and the piston is held against the annular valve seat
462 by fluid pressure in the chamber 424. Concurrently, the surface
444 of the piston 428 is spaced from the annular vale seat 462.
This position permits the maximum fluid flow between the first port
482 and the fourth port 502 and between the fifth port 504 and
third port 486. This flow moves the blade 22 quickly and with
maximum force, to cut the tough object.
[0117] When the pivoted position of the blade 22 begins to catch up
with the position indicated by the finger loop handle 66, the
difference link 362 begins to pivot about the pin 366 due to
movement of the pivotable blade relative to the position of the
finger loop handle. The difference link 362 causes the stem 400 to
move axially outward of the servo control valve 84 to the position
illustrated in FIG. 17E from the position illustrated in FIGS. 17C
or 17D. The conical surface 448 moves closer to the piston 426 and
the piston 428 moves closer to the valve seat 462. Fluid flow from
the first port 482 to the fourth port 502 and from the fifth port
504 to third port 486 continues but at a reduced rate. The blade 22
still is forced to close but at a slower closure rate.
[0118] The cutting action of the blades 22, 24 can be stopped at
any time by stopping the finger loop handle 66 at any position
between its travel limits. The blade 22 will then stop at a
position corresponding to the relative position of the finger loop
handle 66. This will cause the difference link 362 to maintain a
neutral position in which fluid pressure, applied to either chamber
184, 188 of the actuator 88, is not increased.
[0119] To open the shears 20 from the position illustrated in FIG.
1 towards the position illustrated in FIG. 2, the operator manually
pivots the loop handle 66 away from the frame 62. The difference
link 362 pivots counterclockwise about the pin 344 to force the
actuator link 386 to pull the stem 400 outwardly of servo control
valve 84. This action provides fluid flow from the control valve to
the open chamber 184 in the actuator 88. Fluid pressure in chamber
184 forces the power rod 166 to move axially inward into the
actuator 88 and causes the drive link 102 to pivot clockwise about
the pin 134. This imparts a force to pivot the blade 22
counterclockwise about the axis AA in a direction towards the open
position relative to the fixed blade 24.
[0120] When the difference link 362 pivots counterclockwise about
the pin 344, the stem 400 is caused to move axially outward of the
servo control valve 84 from the position illustrated in FIG. 17E to
the position illustrated in FIG. 17F. The right conical surface 448
engages the piston 426 to block fluid flow to the "cut" chamber 188
through the fourth port 502. The second port 484 remains blocked by
the piston 426. The left conical surface 448 disengages the piston
428 to allow fluid flow to the "open" chamber 184 through the fifth
port 504. The third port 486 is closed by the piston 428. Pressure
in the chambers 184 and 188 equalizes on either side of the piston
168 to stop movement of the rod 166 and blade 22.
[0121] The difference link 362 and stem 400 are returned to their
respective neutral positions. The stem 400 is centered in the servo
control valve 84 in the first position again, as illustrated in
FIG. 17G which is the same as FIG. 17A. Equal fluid flow, or no
fluid flow, occurs from the first port 482 to the fourth port 502
and fifth port 504. Exhaust to the second and third ports 484, 486
is permitted if needed,
[0122] If the blade 22, during a cutting action, overshoots the
desired position indicated by the finger loop handle 66, the servo
control valve 84 can compensate, as illustrated in FIG. 17H. The
difference link 362 pivots clockwise about the pin 366 due to the
excessive movement of the blade 22, The stem 400 is moved axially
outward of the servo control valve 84 to the position illustrated
in FIG. 17H. The piston 426 is spaced from the annular valve seat
462 to permit fluid flow from the "cut" chamber 188 through the
fourth port 502 to exhaust through the second port 484. The piston
426 engages conical surface 448 to block fluid flow from the first
port 482. At the same time, the piston 428 engages the annular
valve seat 462 but is spaced from the left conical surface 448.
This blocks fluid flow to exhaust through the third port 486 while
permitting fluid flow from the inlet first port 482 to the open
chamber 184 through the fifth port 504. This flow causes the piston
168 and rod 166 to move inward of the actuator 88 to stop and
reverse the cutting action of the pivotable blade 22.
[0123] Other uses than the power operated shears are also
contemplated for the tool of the present invention. For example,
the tool can be used, without limitation, as power operated pliers,
crimpers, clamp, caulking gun or other tool in which it is
desirable to have reversible, controllable, force multiplied and/or
slower speed at the end of relative movement between members.
[0124] Thus, while preferred embodiments of the invention have been
disclosed, various modifications and alterations can be made
thereto without departing from the spirit and scope of the
invention set forth in the appended claims.
* * * * *