US2870538A - Cable cutter - Google Patents

Description

Jan. 27, 1959 v H. H. TOWNSHEND, JR 2,870,533

CABLE CUTTER Filed March 11, 1958 2 Sheets-Sheet 1 INVENTOR Hnrz "H 7Z7wnsher 2d, Jr.

ATTORNEYS Jan; 27, 1959 H. H. TOWNSHENDQJR 2, 7

1 CABLE CUTTER Filed March 11, 1958 2 Sheets-Sheet 2 INVENTOR Henn H. 75umshend Jr.

ATTORNEY5 3 Claims. (Cl. 30-254)- This invention relates to cable cutters, and' relates more particularly to cable cutters of the type employed United States Patent O for cutting cables up to a diameter of three: and a quarter inches or larger and which may be employed to cut both insulated and uninsulated cables, and both solid and stranded cables.

One object of the invention listo provide an improved cable cutter of the character described above.

proved contour to make the cutting of large-diameter cables easier.

Still another object of'the invention is to provide a cable cutter in which each blade is provided with an improved guide extension for cooperation with the other blade and for cooperation with thecable during the cutting operation.

Further objects of the invention will be apparent from the following detailed description of the presently preferred form of the cable cutter shown in the drawings by way of example.

In the drawings:

Fig. 1 is a fragmentary top plan view illustrating my improved cable cutter and illustrating the blades'of the same in their positions preparatory to cutting shown in phantom;

Fig. 2 is a fragmentary side elevational view of the cutter;

Fig. 3 is a fragmentary top plan view of the cutter illustrating the blades of the same in their fully closed positions;

Fig. 4 is an enlarged sectional view taken on line 4-4 of Fig. 1;

Fig. S'is a top plan view of one of the blades of the cutter;

Fig. 6 is a diagrammatic-view illustrating the blades a cable of the cutter as they start to slice into a cable at the v of the Fig. 9 is a similar view showing a subsequent stage of I the cutting operation, the last-named stage being almost the final stage of the cutting operation.

In the drawings, the blades of the cutter, which may be of identical form, are indicated generally at 10. By .way of example, the blades are shown in association with blade-operating toggle levers 11.- As shown in Fig.4, the blades 10 are fulcrumed on a bolt 12 passing through the outer end of a tubular support 13. The toggle levers 11 extend through slots 14 in the support 13 and each has at one end a common pivot 15 mounting the links on the outer vend of an actuating rod 16 slidable in the tubular support 13.

Each blade 10 in the position of Fig. 1 is elongated generally lengthwise of the support 13 and is provided with a shank portion 10' thickened, as at 17, for added 2,870,538 Patented Jan. 27, 1959 strength. The thickened portion 17 of each blade is slotted, as at 18. The ends of the links 11 remote from the pivot 15 extend into respective slots 18 and are pivoted to the blades, as at 19. The arrangement is such that, when the actuating rod 16 is moved toward the outer end of the tubular support 13, the blades are moved in a closing direction and, when the rod 16 is moved in the other direction, the blades are moved in the opening direction. Movement may be imparted to the actuating rod 16 by any suitable, means (not shown) such as a fluid-operated piston, for example.

Reverting now to the blade construction, it may be noted that each blade. 10 has a planar face 20 and a reverse face 21 tapered, as at, along the entire length of the cutting edge. As shown in Fig. 4, the planar faces 20 of the blades are arranged in opposing relationship and slide over one another during the'cutting operation. As the cutting edges of the respective blades. operate in almost the same plane during the cutting operation, it is important that the blades be maintained in their proper relationship to each other so that the cutting edge of one slides by the cutting edge of the other. In this connection it may be noted that during the cutting of a heavy cable there is a tendency for the blades to twist or turn on their longitudinal axes. This tendency is caused by the force applied to the blades to effect a cut in a heavy cable, and by the resistance of the cable to'the cutting movement of the blades. The tendencyof the blades to twist or turn on their longitudinal axes is highly objectionable in a cable cutter as it usually results in the blades meeting and obstructing one another instead of passing by one another during the cutting operation. To effectively inhibit the aforementioned twisting or turning tendency, the blades of my improved cutter are provided with guide extensions 23, one extension 23 being formed on one blade and one extension 23 being formed on the other blade. Each blade exten-' sion, formed as an integral lug, cooperates with the planar surface 20 of the other blade to maintain the blades in their respective planes.

When the blades assume their initial cutting positions (Fig. 6), the guide extensions 23 extend well forwardly of the fulcrum 12 and provide substantial bearing surfaces for the blades. As best shown in Fig. 5, each extension 23 has a forward surface 24 formed on an are which approximates an extension of the arcuately formed portion of the blade which is provided with a cutting edge. Turning now to the particular contour of the cutting edge of each blade, it will be noted that, as shown in the last-mentioned view, the outer or forward extremity of each blade is provided with a substantially straight chisellike cutting-edge portion 25 which extends in a plane ap proximately parallel to the longitudinal axis of the blade. The edge portion 25 at its inner or rear extremity merges with a rather sharply rounded cutting-edge portion 26 which, in turn, merges with an arcuate cutting-edge portion 27 formed on a longer radius. As shown in Fig. 5, the edge portion 27 extends to a point not far from the point at which the blade is fulcrumed. The contour of the cutting edges of the blades is such that when the blades are partially closed (see Fig. 8) the blades define an opening therebetween which is oval or of teardrop shape, the larger or more rounded end of the oval being remote from the fulcrum of the blades and theapex of the oval being nearest the fulcrum. Hence it may be said that the curved cutting-edge portion of each blade is of semi-oval form with the apex end of the edge portion nearest the fulcrum of the blade.

The operation of the cable cutter will be understood from the foregoing disclosure and from the diagrammatic views of Figs. 6 through 9, illustrating a cutting operation. When a large cable is interposed between the blades hold the cable outwardly toward the outer ends of the blades. As the blades close from .the position of Fig. l to the position of Fig. 6 to commence :the cutting operation, the bearing contact of each blade extension with its companion blade is increased and the cable is permitted a slight degree of movement between the blades 1n the direction of the fulcrum. In the blade positions shown in Fig. 6, the extensions .remain engaged with what may be termed the inner side of the cable while the outer chisel-like edge portions 25 commence to cut the side of I .the cable away from the fulcrum. The chisel-like edge portions 25 are very effective for cutting cable insulation. The effectiveness of the chisel-like edge portion 25 of each blade is believed to be due to its slicing action and,

in this connection, it may be noted that, as shown more V particularly in Fig. 7, the edge 25 slices across the cable instead of chopping down toward the longitudinal axis of the latter.

It will be noted that, owing to the semi-oval parts of the cutting edges, the outer end portions of the blades, A

which have the least mechanical advantage, commence the out well. before the shearing force is resisted by engagement of the cable with the entire areuately formed cutting edge portions. In other words, as the shearing operation is commenced, almost the entire available shearing force is utilized to cut the outer side of the cable with the parts of the blades which have the least mechanical advantage. Furthermore, due to the oval formed between the blades and having its apex nearest the fulcrum (see Fig. 7), the cable, after the cutting operation has commenced, will not squeeze out between the blades, even though the outer ends of the blades have not overlapped, but will tend to be forced in the direction of the fulcrum. As the blades move from the positions of Fig. 7 to the positions of Fig. 8, the cable is cut from the outer side toward the side nearest the fulcrum. As shown in Fig. 6, the distal ends of the guide extensions 23 of the blades are well forward of the fulcrum. The lastmentioned ends of the extensions are swung rearwardly during the cutting operation but, even when the cut is nearly completed, as shown in Fig. 9, these ends remain forward of the fulcrum. However, the blade guidance function of the extensions is no longer needed when the outer ends of the blades have overlapped, as shown in Fig. 8. It is important that the guidance lugs 23 extend forwardly of the fulcrum until the outer ends of the blades have overlapped. When the blades are moved to their positions shown in Fig. 3, the blades are fully closed and the cut is completed.

In accordance with the foregoing disclosure, there is provided an improved cable cutter which is of simple construction and yet very efiicient and effective in use, especially for cutting cables of large diameter. One advantage of the cable cutter resides in the particular contour of the cutting edge of each blade. This contour facilitates cutting through heavy cables. Permanent deformation or squashing of heavy cables during cutting is inhibited. Another advantage resides in the provision .of.theblade.guidanceextensious which resist torque and twisting of the blades on their longitudinal axes during the cutting operation, and which also serve to position cables between the blades.

While only one form of the cable cutter has been illus- 'trated in the drawings and described above, it will be apparent to those versed in the art that the cable cutter is susceptible of various modifications and changes in details without departing from the principles of the invention and the scope-of theclaims.

said extensions being engageable with a cable interposed between the blades to position the cable relatively to the blades at the commencement of the cutting operation. 2. A cable cutter-comprising a pair of blades pivotally interconnected and having opposing cutting-edge portrons defining :therebetween an opening when the blades are partially closed, ea'ch bl a'de having a guide extension cooperating with the other blade to resistblade torque during a cutting operation, the extensions being formed as lugs on the blades and providing substantial bearing areas wellforward of the pivotal axes of the blades when the blades are swung to overlap their outer ends, and sald extensions being engageable with a cable interposed between the blades to position the cable relatively toth'c bladesat'the commencement of the cutting operation, the extensionshaving curved forward surfaces forming continuations of the parts of the blades which are provided with said cutting-edge portions. I

3. A cable cutter comprising a pair of blades pivotally interconnected and having intermediate their ends opposing cutting-edge portions of at least partially curved form defining 'therebetween an opening when the blades .are partially closed, the blades having substantially straight cutting-edge portions of chisel-like form an proaching one another, the last-named cutting-edge portrons extending to substantially the outer extremities of the blades and merging with the respective first-named portions, each blade having a guide extension cooperating with the other blade to resist blade torque during a cutting operation, the extensions being formed as lugs on the blades and providing substantial bearing areas well forward of the pivotal axis of the blades when the blades are swung to overlap their outer ends, and said extensions being engageable with a cable interposed between the blades to position the cable relatively to the chisellike cutting-edge portions of the blades at the commencement of the cutting operation, each extension having a curved forward surface forming a continuation of the part of the blade which is provided with the cuttingedge portion of at least partially curved form.

References Cited .in the file of this patent UNITED STATES PATENTS

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