Manual sheet metal cutter
A manual sheet metal cutter (10) with a movable upper blade (12B) laterally offset from and integrally formed with a lower movable handle (12A) pivotally connected to, and sandwiched between, a stationary blade member (14) on the offset side of the movable blade (12B) and a stationary handle (16), of which are all pivotally connected together by a single fastener (11) defining a pivot axle. A rearward extension (14A) of the stationary blade (14B) defines an alignment section which bears against a mating alignment portion of an intermediate section (12C) of the movable blade member (12) to maintain the blades (12B, 14B) in correct cutting relationship. The fastener (11) enables pivotal adjustment of the angle of the stationary handle member (16) relative to the stationary blade member (14B), and an arcuate lower edge (14C) of the stationary blade member (14) defines a rocker to facilitate rocking, cutting movement.
BACKGROUND OF THE INVENTION
This invention generally relates to a scissor-like cutter and, particularly to a manual sheet metal cutter.
Scissor-like cutters, generally, and a manual, sheet metal cutter are well known as shown by U.S. Pat. Nos. 176,553 issued Apr. 25, 1876 to Schafer; 387,283 issued Sept. 7, 1888 to Ducommum; 1,368,431 issued Feb. 15, 1921 to Greenberg; 1,691,989 issued Nov. 20, 1928 to Lonsway; 2,117,224 issued May 10, 1938 to Soss and 2,400,220 issued May 14, 1946 to Bell and 4,463,497 issued Aug. 7, 1984 to O'Keefe.
Only the offset snips shown in O'Keefe U.S. Pat. No. 4,463,497 is especially designed for cutting sheet metal. However, this device requires multiple pivot connection and a complicated assortment of springs, arms and other parts to enable a relatively stationary lower blade and offset handles needed to facilitate cutting sheet metal. Moreover, the cutting blades are not interchangeable with different handles. The multiple pivot points undesirably result in movement of both handles relative to the underlying stationary blade during cutting movement, while the angle of the upper handle cannot be adjusted except during cutting movement. The blades are straight and cannot easily be used to cut curves, while the lower blade member lacks any means, other than the blade itself, for facilitating rocking movement of the lower blade to assert the cutting movement.
SUMMARY OF THE INVENTION
It is therefore a principal object of the present invention to provide a manual sheet metal cutter which is simpler in construction, more versatile and more effective then known sheet metal cutters.
This objective is achieved in part by provision of a manual sheet metal cutter with a generally T-shaped member having an elongate handle defining a base of the T-shaped member joined to an intermediate section of a stationary blade member defining a cross of the T-shaped member, a generally V-shaped member having an elongate handle defining one leg of the V-shaped member and a movable blade member defining another leg of the V-shaped member, and means for pivotally connecting the T-shaped member to the V-shaped member with the movable blade member and stationary blade member in cooperative cutting relationship.
The objective is also partly achieved through provision of a manual sheet metal cutter with a first member having a lower stationary blade member with a lower stationary blade, a laterally offset upper stationary handle, an axle member for pivotally connecting the upper stationary handle to the lower stationary blade in lateral offset relationship and an upper movable blade with a lower movable handle underlying said laterally offset stationary handle and pivotally connected to said axle in cutting relationship with said lower stationary blade.
Achievement of the objective is also obtained with a manual sheet metal cutter having a first, elongate, planar member having a hand grip at one end and a connector portion at an opposite end substantially aligned therewith and having one side, a second, elongate member with a planar hand grip at one end substantially aligned with the hand grip of the first member, an intermediate section having a first side adjacent one side of the first, elongate, planar member and a first curved blade which curves outwardly away from said one side of the first elongate planar member and having a second side opposite the first side, a second curved blade member with a second curved blade with a side in cutting relationship with said second side of the first curved blade and means for securing together the first member and the second member with the first curved blade sandwiched between the connector portion of the first member and the second curved blade.
The objective is also accomplished by providing a manual metal sheet cutter with a first, elongate member having a movable handle lying in a handle plane at one end, a movable upper blade lying in a blade path laterally offset from the handle plane and an intermediate section extending in a lateral direction to join together the movable handle and the movable blade, an elongate, stationary, lower blade member in the blade path lying beneath the movable blade and having an elongate, stationary, lower blade in scissor-like cutting relationship therewith, a second elongate member with a stationary handle lying in the handle plane and means at an opposite end for connection with the elongate, stationary, lower blade, and a fastener coupled with the connection means for fixedly securing the opposite end of the second elongate member to the elongate, stationary, lower blade member and for securing the first elongate member to the elongate, stationary elongate blade member is provided.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing objects and advantageous features of the invention will be explained in greater detail and others will be made apparent from the detailed description of the preferred embodiment of the present invention which is given with reference to the several figures of the drawing, in which:
FIG. 1 is a side view of the preferred embodiment of the manual sheet metal cutter of the invention;
FIG. 2 is a plan view of the preferred embodiment of the manual sheet metal cutter of FIG. 1 but in which the cutter is provided with curved blades; and
FIG. 3 is a perspective illustration of use of the manual sheet metal cutter of FIG. 2 to make a curved cut.
Referring now to the drawings, particularly FIG. 1, the preferred embodiment of the sheet metal cutter 10 advantageously is formed of three simple elements pivotally interconnected by a single fastener assembly 11. Preferably, all the elements are made of steel. One of the three elements is defined as a first, elongate generally V-shaped member 12 having a lower, movable handle 12A and an upper movable cutting blade 12B joined together by an intermediate section 12C. A second element is defined by an elongate, stationary, lower blade member 14 which has a rearward extension 14A on one side of fastener assembly 11 and a lower, stationary blade 14B on the other side of fastener assembly 11. The elongate, lower stationary blade member 14B lies in a blade path directly beneath the movable blade 12B in scissor-like cutting relationship therewith. The third element is defined by a second, elongate, planar member 16 having a stationary handle 16A at one end lying directly above the lower, movable handle 12A in a handle plane aligned therewith. Means including a bore 16B, FIG. 2, is provided at the opposite end of the second member for connection with the elongate, stationary, lower blade 14B by means of the fastener assembly 11.
Referring also to FIG. 2, members 12 and 14 also have bores 12D and 14C, respectively, aligned with bore 16B for receipt therethrough of the shank 11A of a bolt having a bolt head 11B on an outer side of member 16 and a threaded end 11C to which a threaded nut 11D is fastened. Preferably, a lock washer 11E is interposed between the nut 11D and the outer side of member 14. The portion of the shank 11A passing through the bore 12D is not threaded to enable smooth pivotal movement of the upper movable blade 12B relative to the lower stationary blade 14B. Advantageously, the fastener assembly 11 couples with the connection means defined by 16B to secure the end of the second elongate member 16 to the elongate, stationary, lower blade member 14 while at the same time securing the first, elongate, V-shaped member 12 to the stationary, lower blade member 14. The need for multiple pivot axles and multiple connections to secure together the various parts are eliminated.
In keeping with one aspect of the invention, a tight fit between the shank 11A and the bore 16B fixedly holds the upper stationary handle 16A at a preselected angle relative to the lower stationary blade 14 during free pivotal movement of the upper movable blade 12B relative to the lower stationary blade 14B while at the same time enabling selected, adjustable pivotal movement of the upper stationary handle 16A relative to the lower stationary blade 14B, as described. Thus, the second elongate member 16 and the lower, stationary blade member 14 are paired together to define a T-shaped member with the second elongate member 16 defining the base of the T and the stationary blade member 14 defining the cross member of the T.
Still referring to FIG. 2, another advantageous feature of the preferred invention resides in the fact that the stationary blade member 14B and the rearward extension 14A are integrally formed of a single piece of metal, such as steel, and together define a common underlying rocker with a rocker edge surface 14C which extends rearwardly of the pivot axle of fastener assembly 11. By applying force from stationary handle 16A through the second elongate member 16 to the stationary blade member 14 at different selected adjustable angles relative thereto and to the plane of an underlying workpiece 20, FIG. 3, the lower stationary blade 14B can be selectively rocked back and forth to facilitate relative cutting movements between the upper movable blade 12B and the stationary blade 14B.
Another advantageous feature results from the arrangement of an inner side 14A' of the rearward extension 14A of the lower, stationary blade member 14 in bearing aligning relationship with an alignment side 12C' of the intermediate section 12C of the generally V-shaped, first member 12.
Another feature of the preferred embodiment of the manual sheet cutter 10 is that the elongate handle 12A defining one leg of the V of the V-shaped member 12 is laterally offset from the movable blade 12B of the other leg of the V. The intermediate section 12C has a laterally extending section 12C" to achieve the offset. Likewise, the upper stationary handle 16A is laterally offset from the stationery blade 14B in the same direction and to the same extent as the handle 12A is offset from the stationary blade 14B. Accordingly, the handles 12A and 12B are aligned with one another in a shared handle plane.
Thus, the intermediate section 12C, apart from the laterally extending section 12C", is sandwiched between the connecting end or connector portion 16B of the upper stationary handle member 16C, and the rearward extension, or alignment portion, 14A of the stationary blade member 14.
Another feature of the invention is that the single upper stationary handle is alternatively usable with different matched sets of stationary, lower blades 14B and movable, upper blades 12B. As seen in FIG. 1, the blades 12B and 14A are substantially planar. Alternatively, the blades 14B and 12B are curved as shown in FIG. 2 to facilitate the cutting of curves, such as curve 22 of FIG. 3. The blades 12B and 14B curve outwardly away from the handles 12A and 16A. However, advantageously, the stationary handle member 16 is mountable on either side of the blades 12B and 14B to enable use of the handle member 16 with left hand curved blades, as shown in FIG. 2, and with right hand blades which are mirror images of the left hand blades shown in FIG. 2.
While a particular embodiment has been disclosed as the best mode of practicing the invention, it should be appreciated that variations may be made without departing from the scope of the invention as defined in the appended claims.