US2708480A - Self-propelled sheet metal shear - Google Patents

Description

May 17, 1955 c. F. ENGEL v2,708,480

SELF-PROPELLED SHEET METAL SHEAR Filed Nov. 2, 1953 :4 2 I] Y2 23 7 I? ma F F|G.6 18

I INVENTOR. 57 11 CHARLES FRANK ENGEL 35 52 M, ATTORNEY United States Patent SELF-PROPELLED SHEET METAL SHEAR Charles F. Engel, Sparta, Ill.

Application November 2, 1953, Serial No. 389,624

11 Claims. (Cl. 164-76) This invention relates to sheet metal shears, and particularly to shears having disc cutters for cutting rectilinear sheet edges, as for duct work and the like.

Rolling shears have been used from time to time with sheet metal work tables equipped with sheet-holding clamps, for the purpose of cutting long, straight or tapering sheet metal pieces. With light weight sheet metal, as is used for ducts, a difiiculty frequently encountered is the buckling of the sheet during the cutting operation. With heavier weight sheet metal, despite the use of clamps, rolling shears have shown a tendency to draw the sheet metal off or move it farther onto the work table; and with light weight sheets, to cause buckling. These undesirable effects have been multiplied when attempts were made to apply power to the shears.

A principal purpose of the present invention is to overcome these problems and provide a power-operated shear for cutting sheet metal accurately and without deviating from an intended rectilinear.

A further purpose is to provide a self-propelled shear for sheet metal which will overcome the tendency toward moving the sheet metal onto or off of the work table.

A still further purpose is to provide a rolling shear having adjustable mechanism whereby this sheet-moving tendency may be overcome for sheets of metal of different thicknesses and tempers.

In the accompanying drawings:

Figure 1 is an outer side elevation of a removable shear embodying the present invention, shown without the carriage therefor;

Figure 2 is a plan view of the removable shear shown in Figure 1;

Figure 3 is an inner side elevation of the carriage for the shear of Figure 1;

Figure 4 is an aft end view of the carriage of Figure 3, shown mounted on a track secured to the side of a work table;

Figure 5 is an inner side elevation of the assembled shear, shown without a track;

Figure 6 is an aft end view of the assembled shear of Figure 5;

Figure 7 is a sectional view taken along line 7-7 of Figure 5; and

Figure 8 is a sectional view similar to Figure 7, but showing alternate resilient alignment means.

In describing the drawings, and throughout this specification and claims except where another meaning is indicated, the terms inward and inner refer to the work-table side of the shear, and outward and outer, the side away from the work-table; forward means the direction in which the shear propels itself, and also its end which faces that direction, and aft" means the opposite of forward.

The shear illustrated in these drawings consists of two principal portions, a removable shear, generally designated 1 and shown separately in Figures 1, 2 and 3;

2 ,708,480 Patented May 17, 1955 and a carriage, generally designated 2 and shown separately in Figure 4.

In Figure 4, the carriage is shown mounted on an elongated horizontal rectilinear track, designated a, secured by brackets such as the bracket b to the side of 'a work table generally designated 0 having an upper 6 which extend spacedly over the top of the rectilinear track a; and which support the vertical trunnions 7 inward of the track a. Beneath said trunnions 6 are mounted the inner rollers 8 which bear against the inner side of the upper margins of the rectilinear track a.

Near the lower portion of the rectilinear track a, the carriage plate 5 has a roller aperture 9 (see Figure 5), outward of which is the lower end of a vertical roller pin 10, which pin is welded to the outer side of the car: riage plate 5 above the aperture 9. The vertical roller pin 10 supports an outer roller 11 protruding through the roller aperture 9, as shown in Figure 4, to bear against the outer surface of the rectilinear track a near its lower edge.

On the inner side of the carriage plate 5 near its lower edge is a welded abutment strip 12. Referring to Figures 4, 5 and 6, it is apparent that the top rollers 3, the inner rollers 8, the outer roller 11 and the abutment strip 12 permit the carriage 2 to ride along the rectilinear track a and be held thereon securely by the weight of the removable shear 1.

At the forward end of the carriage 2 are protruding upper and lower lead portions 13, 13', each having a substantially horizontal upper bearing face 14, 14, respectively, and each further having welded to the outer side thereof the vertical aligned upper and lower caster pins 15, 15'.

The removable shear 1 is mounted to the carriage 2 and supported thereon by upper and lower caster lugs 16, 16' having aligned lug bores 17 on the caster axis designated e, as shown in Figures 1, 2, 3 and 5. The lower faces of the caster lugs 16, 16 bear upon and against the upper bearing faces 14 and 14' and permit the shear 1 to swing in a horizontal plane about the caster axis e. The upper and lower caster lugs 16, 16 are welded to the forward end of a shear frame outer plate 18, which is the principal structural member of the removable shear 1. The shear 1 will now be described in detail.

The shear frame outer plate 18 is located outward of the caster axis e, as shown in Figure 7. Its upper edge is referred to hereafter as the sloping scrap deflector edge 19, as shown in Figure 1, which commences below the plane of work d, established by the work table 0 of Figure 4 and extends aft and upward. On its inner side, above the plane of work d, and adjacent its aft end, is mounted a cross-over insert portion 20, which sup ports an upper inner plate 21 inward of the lug bores 17, having at its top an upward-extending handle 22.

Cutters of the shear 1 are arranged as follows: An idling disc cutter 23 is supported on an upper lateral cutter axis 24 so that it is on the outer side of the upper inner plate 21, its cutting edge being outermost. A driven disc cutter 25 is supported beneath and slightly aft of the upper lateral cutter axis 24, on a lower lateral shaft 26, and on the inner side of the shear frame outer plate 18, so that the idling cutter 23 and driven cutter 25 are held spaced in cutting relationship adjacent each other,

as shown in Figures 3 and 5. Inasmuch as the crossover insert portion 20 is inserted between the upper inner plate 21 and the shear frame outer plate 13 at the rear portions thereof, the idling disc cutter 23 and the driven disc cutter 25 operate in a cutter opening designated 27 in which sheet metal may be inserted. The driven cutter 25 has a knurled peripheral portion 28, as shown in Figures 2 and 6. This knurled edge portion 28 engages the lower surface of metal sheets inserted in the cutter opening 27 as the cutter 25 rotates under power supplied by the motor 34. The engagement of the knurled edge portion 28 adds to the tractive effort exerted by the driven cutter 25. This effort is referred to as the tractive force, and it pulls the shear 1 and carriage 2 horizontally along the rectilinear track 1: under propulsive power transmitted as hereinafter described.

The driven disc cutter 25 is secured adiaccnt the inner end of the lower lateral shaft 26 penetrating the shear frame outer plate 18. The portion of the shaft 26 projecting inward beyond the cutter 25 is accommodated in an adjacent clearing hole 29 in the carriage plate 5, shown in Figure 5.

To the outer end of the shaft 26 is secured a pinion gear 30, driven by a worm gear 31 mounted on the forward end of a longitudinal shaft 32 which is supported by a sleeve 33 welded to the outer side of the shear frame outer plate 18. Power is supplied to the longitudinal shaft 32 from an electric motor 34 mounted parallel to the shaft 32, through sheaves 3S and a V-belt 36. The motor 34 is mounted by a U-bracket 37 to a horizontal frame plate 38 welded to the lower edge of the shear frame outer plate 18 beneath the sleeve 33. A gear guard box 39 is welded to the shear frame outer plate 18 and the horizontal frame plate 38, giving it further support.

As described to this point, the removable shear 1 may be mounted onto the carriage 2 by slipping its upper and lower caster lugs 16, 16' over and onto the upper and lower caster pins 15, 15 of the carriage 2. As so mounted, the removable shear 1 would be free to swing in a horizontal plane about the vertical caster axis 6, until lateral contact was made between the inner side of the driven cutter 25 and the outer side of the carriage plate 5. The alignment of the parts is shown in Figure 7, which is a section taken along line 77 of Figure 5.

in order to establish an initial position, an adjustment screw 49 is inserted through a cleared hole 41 in the carriage plate and supported in position in a tapped hole 42 in the shear frame outer plate 18. A spacer 43, which may be tubular as shown in Figure 7, is mounted on the shaft of the screw 40 and inserted between the shear frame outer plate 18 and the carriage plate 5. Its width establishes the initial angular position shown in Figure 7; and a compression spring 44, similarly mounted on the shaft of the screw 40 but which operates between the head of the adjustment screw 40 and the carriage plate 5, tends to restore this position when disturbed. It is noted that this initial position heads the shear 1 slightly outward of parallelism with the track a. The amount of outward heading is usually of the order of 2, but may be readily established under particular conditions by trying out spacers, such as the spacer 43, of varying thicknesses.

As soon as the shear 1 tractively engages and begins to propel itself across the metal sheet being cut, the castering'tendency of the machine manifests itself. It can progress only in the direction which the carriage moves the caster pins 15, Therefore its tractive force causes it to caster, or tend to swing into line behind the caster pins 15, 15. Hence the cutters 23, tend to follow a line parallel to the rectilinear track a. The bearing of the inner face of the driven cutter 25 against the outer sheared edge of the sheet just aft of the point of cut tends to assure continued linearity of the cut edge with the forward movement of the castering axis e.

irregularities in the metal sheet, for example, in its grain structure, may cause a slight temporary angular deviation of the shear 1 from true alignment with the rectilinear track a. The machines castering tendency, subject to the resiliency of the spring 44, as modified by adjusting its tension by the screw 40, tends to restore the cutters 23, 25 to proper alignment as soon as the irregularity has been passed.

As a cut is started, the spring 44 substantially minimizes the possible initial angular deviation from the intended line of cut. After a 'cut has been started, the spring 44 is of less importance. The fact that the shear 1 is self-aligning substantially eliminates the tendency of outside forces to divert it from a true line of cut. Accordingly, there results a out which follows the line of the rectilinear track a without either pulling the sheet metal from the table or pushing it farther onto the table. irregularities in line of cut arising from the castering freedom of the shear 1 are too slight to be noticeable in the finished product, although its freedom'to accommodate itself to irregularities is apparent when the mechanism is viewed while operating.

A factor which favors the accuracy of the present shear is the stagger of the axis 24 of the idling cutter 23 forward of that of the lateral shaft 26. This stagger presents a larger portion of the inner face of the driven cutter 25 against the cut edge of the sheet, which stabilizes the movement of the shear.

An alternative arrangement for aligning the carriage 2 and the shear 1 resiliently with respect to each other is shown in Figure 8. Instead of a spacer 43 and spring 44, as shown in Figure 7, there is utilized in the embodiment shown in Figure 8 a pair of opposed compression springs 45. These are mounted on the shaft of the screw 49 on opposite sides of and bearing against the carriage plate 5, and urge the said shear frame outer plate 18 and the carriage plate 5 resiliently in parallel alignment. In this arrangement the shear 1 is likewise free to accommodate by angular movement for any irregularities which might be encountered in the sheet. Thus, rcctilinearity of cut is preserved in a manner much similar to that which has been heretofore described.

The idling cutter 23 is preferably mounted within the inner plate 21 in an eccentric spacing insert 46, so that slight adjustments in overlap of the cutters 23, 25 may be made to accommodate sheets of varying thicknesses.

Other modifications in structural details, to adapt the present invention to varying uses will be apparent to those skilled in the art. Accordingly, the present invention is not to be construed narrowly but coextensive with the inventive principles herein disclosed.

I claim:

I. A shear adapted to be propelled along a fixed horizontal path, comprising a carriage moveable along such path, a cutter-bearing frame borne by the carriage and adapted to travel normally in parallel alignment therewith, and cutter means on the frame having a shearing edge disposed in a vertical plane and positioned to cut in the direction of forward carriage movement, together with vertical pivot means connecting the carriage to the frame in advance of the cutter means, the pivot means moving with the carriage along such path and permitting the frame limited angular movement in a horizontal plane into and out of its normal parallel alignment with the carriage, whereby forward movement of the carriage tends to caster the frame into such parallel alignment, the cutter means including a rotatable cutter mounted on a lateral shaft, together with motor means and power-transmission means engaging the motor means to drive the rotatable cutter so as to tractively engage and progressively shear a sheet of material against which the retatable cutter is brought and thereby move the carriage progressively forward along such path.

2. A self-propelled shear for sheet material adapted for cutting during forward movement along a rectilinear track extending in a horizontal path, comprising a vertical carriage plate having means supporting it on and in parallel alignment alongside such track and having vertical pivot means at its forward portion, further comprising a shear frame mounted to the carriage plate by the pivot means and thereby permitted limited angular movement in a horizontal plane behind the pivot means into and out of parallelism with the carriage plate, a shearing cutter mounted to the shear frame and adapted to shear in a vertical plane and in the direction of forward movement, the shearing cutter having cutter means including a rotatable cutter on a lateral shaft mounted to the frame aft of the pivot means, a motor, and power-transmitting means engaging the motor to drive the rotatable cutter whereby the said cutter wi l exert a tractive force against a sheet of such sheet material as may be placed in engagement thereagainst, the tractive force being reacted against the pivot so as to advance the frame along such rectilinear track.

3. A self-propelled sheet metal shear as defined in claim 2, the cutter so driven being disc-like and having a knurled edge for tractively engaging such sheet of metal to be sheared thereby.

A self-propelled sheet metal shear as defined in claim 2, the cutter means including a rotatable, idling disc cutter mounted to the frame on a shaft above the level of and inwardly adjacent the line of cut, the motordriven cutter being mounted to the frame on a shaft below the level of and outwardly adjacent the line of cut.

5. A self-propelled sheet metal shear as defined in claim 2, the said motor-driven cutter being mounted to the frame below the level of and outwardly adjacent the line of cut, the frame having a scrap-deflecting portion sloping upward aft of the said motor-driven cutter to a point above said line of cut, further having an upper frame portion extending forward therefrom, above the level of the line of cut and on the inner side thereof, the cutter means including a cutter element mounted to said upper frame portion and positioned to cooperate with the said motor-driven cutter to sever the sheet progressively and drive that portion of the severed sheet outward of the line of cut, up and over the scrapdeflecting portion of the frame.

6. A self-propelled sheet metal shear as defined in claim 2, the said motor-driven cutter being mounted to the frame on a first cross-shaft below the level of and outwardly adjacent the line of cut, the frame having a scrap-deflecting portion sloping upward aft of said motordrivcn cutter to a point above the line of cut, further having an upper frame portion extending forward therefrom above the level of the line of cut and on the inner side thereof, the cutter means including an upper idling disc cutter mounted for rotation onto a second cross-shaft in the upper frame portion above the level of and forward of said first cross-shaft.

7. A self-propelled sheet metal shear as defined in claim 2, together with a pivot stop, and spring means yieldingly urging the frame aft of the pivot toward the carriage a predetermined angular amount beyond centered position against said pivot stop, subject to the tendency of the shear to center behind the pivot means under the propulsive traction of the cutter so driven by the motor.

8. A self-propelled sheet metal shear as defined in claim 2, together with balanced spring means engaging the carriage and frame aft of the pivot means and urging the frame pivotally to a position of angular alignment wherein the line of cut is substantially parallel to the path along which the carriage is moveable.

9. A self-propelled sheet metal shear as defined in claim 2, together with a rectilinear track for the carriage adapted for secure mounting along and below the edge of a Work table at such level as to transport the cutter means in cutting relationship at substantially the level of such work table.

10. A self-propelled shear for sheet material adapted for cutting during forward movement along a rectilinear track extending in a horizontal path, comprising a vertical carriage plate having roll means supporting it on and in parallel alignment alongside such track and having vertical pivot means at its forward portion, further comprising a shear frame mounted to the carriage plate by the pivot means and thereby permitted limited angular movement in a horizontal plane behind the pivot means into and out of parallelism with the carriage plate, a shearing cutter mounted to the shear frame and adapted to shear in a vertical plane in the direction of forward movement, the shearing cutter having cutter means including a rotatable cutter on a lateral shaft mounted to the frame aft of the pivot means, a motor, and powertransmitting means engaging the motor to drive the rotatable cutter whereby the said cutter will exert a tractive force against a sheet of such sheet material as may be placed in engagement thereagainst, the tractive force being reacted against the pivot so as to advance the frame along such rectilinear track, the shear frame fur ther having a fixed alignment portion positioned alongside and spaced from the side of the carriage plate opposite such track, and resilient restraint means displaced from the pivot means and yieldingly urging the alignment portion of the shear frame toward parallelism with the carriage plate.

11. A self-propelled. shear for planar material, the shear being adapted for cutting during forward movement along a rectilinear track extending in a path parallel to the plane in which such material is to be placed for shearing, comprising a planar work surface, a rectilinear track mounted parallel to the plane thereof, a carriage having means supporting it on such track and having pivot means perpendicular to the plane of the work surface at the forward portion of the carriage, a shear frame borne by the carriage and connected to it by the pivot means and thereby permitted limited angular movement in a plane parallel to the work surface plane behind the pivot means into and out of parallelism with the track, a shearing cutter mounted to the shear frame and adapted to shear in a plane perpendicular to the work surface and in the direction of forward movement, the shearing cutter having cutter means including a rotatable edged cutter aft of the pivot means on a lateral shaft mounted to the frame, a motor, and power-transmitting means engaging the motor to drive the rotatable cutter, whereby the said cutter will progressively shear into and exert tractive force on a sheet of planar material placed against the work surface and which the cutter may engage, the tractive force being reacted against the pivot so as to advance the frame along said rectilinear track.

References Cited in the file of this patent UNITED STATES PATENTS 609,213 Ridgeley Aug. 16, 1878 733,511 Ridgeley July 14, 1903 1,154,924 Holub Sept. 28, 1915 1,241,313 Wagner Sept. 25, 1917 2,060,600 Weiss Nov. 10, 1936 2,216,108 Brockway Oct. 1, 1940

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