Cable cutters and cable shears of varying types are used for cutting pipes, cables, wires and leads made of copper, steel, glass fibers, or other material.
Existing cable cutters include two intersecting levers articulated by a pivot joint. Each of the two levers which are to be actuated by one hand has a cutting jaw formed above the joint and a handle formed below the joint. Because of the long handles, the user can exert relatively high cutting pressures. In one-handed operation, however, only wires having small cross-sections may be cut because the handwide opening of the handles to accommodate the hand of the user will only permit limited opening of the cutting jaws.
The two intersecting levers are articulated by a common first pivot joint where each of the levers has a handle in its lower section and a cutting jaw in its upper section. That is, the levers have two parts, a front lever section forming the cutting jaw and a back lever section forming the handle. The lever sections are articulated by the pivot joint and are interlockable relative to each other in at least two distinct angular positions.
Many of the cutters have cutting jaws that open or spread apart wide enough to allow cutting of 0.25 inch diameter wire rope. The handles can open to around 7 inches or so to allow a continuous one handed operation and grip. The cutters are generally made up of two symmetrical halves fastened together by a pivot sub-assembly. The mechanical advantage is determined by the length ratio of the handle lever to the jaw lever. Given the restriction that the cutters must be operated in a one handed fashion, the dimensions of the handle lever arm is relatively the same for all cutters and therefore the moment about the pivot is the same. Given this, the mechanical advantage for cutting the wire rope is wholly dependent on the profile of the cutter jaw as it relates to the pivot.
Thus, there exists a need for a hand held cutter which has a mechanical advantage resulting from a short lever arm.
Most hand held wire rope cutting tools have some type of positive stop for the closed position and some type of stop for the open position. One variation of a cutter has a formed handle riveted to a stamped jaw head. This same variation of cutter has both stops built into the soft handle. The disadvantage of having hard materials stop on soft materials is that the soft material will wear more rapidly with continued use.
Other one piece cutters have closed position stops built into the handles below the head. These stops also serve a double function in that they integrate a sleeve crimper. A problem with these dual function stops is that have a pinch point in the area where the hand is placed which could harm the user.
Thus, there exists a need for a hand held cable cutter which has positive stops for both open and closed positions formed integrally with the head and of the same hardness material as the head.
In accordance with one aspect of the disclosure, a hand held cable cutter has a first cutter half which has a first cutting head with a first jaw having a first cutting blade formed on a first edge of the first jaw; a first pivot portion formed in the head; a second cutter half having a second cutting head with a second jaw having a second cutting blade formed on a first edge of the second cutting blade; a second pivot portion formed in the second head; and wherein the first cutting blade has a cutting profile formed between the first pivot portion and said first cutting edge of the first cutting blade and a root formed between a second cutting edge of the first cutting blade and the first pivot portion, wherein the second cutting blade has a cutting profile formed between the second pivot portion and the first cutting edge of the second cutting blade and a root formed between a second cutting edge of the second cutting blade and the second pivot portion, wherein the root and profile of the first cutting blade and the root and profile of the second cutting blade form an overlap between the first and second cutter blades when the cutter is in a closed position.
In accordance with another aspect of the disclosure, a first lever arm is formed between the pivot portion of the first cutting head and an outer edge of the first handle portion in a longitudinal direction.
In accordance with another aspect of the disclosure, a second lever arm is formed between the pivot portion of the first cutting head and an outer edge of the first handle portion in a transverse direction.
In accordance with another aspect of the disclosure, a mechanical advantage is defined by the first lever arm divided by the second lever arm times the handle force which equals jaw force.
In accordance with another aspect of the disclosure, the first cutter half and the second cutter half each has integrated stop portions formed in the first and second cutting heads to limit movement of the cutter halves to an open or closed position.
Other advantages and aspects of the disclosure will become apparent upon a reading and understanding of the following description.
The present disclosure relates to hand held cable cutters that offer improved mechanical advantage by virtue of a short lever arm as defined by the distance from a pivot to a root of a cutter profile. The cutter also has integrated positive stops formed in the head for both open and closed positions.
Referring now to
Referring now to
Referring to
The cutter profile also incorporates the necessary profile geometry to squeeze the wire rope into a triangular shape with two corners 30, 32 defined by the radius R as the cut is being made (see
Referring now to
The mode of function of the cable cutter according to the disclosure is shown in
For cutting a wire or cable, the cable cutter is first brought into the fully opened position shown in
Referring now to
In particular, the disclosure has a unique cutter profile that allows improved mechanical advantage while maintaining limits defined by the jaw opening, one hand operation, and a quality finished cut. The mechanical advantage is defined by the ratio of the lever arms about the pivot. More particularly, referring to
The equation is given by:
(L1/L2)*(handle force)=(jaw force)
Critical dimensions as they relate to the center pivot are listed as follows:
Radius R is 0.079 inches±0.005 inches
Lever Arm L2 is 0.242 inches±0.005 inches
Profile P is 0.125 inches±0.005 inches
Overlap OL is 0.025 inches±.0.017 inches
Referring now to
The cutter is also unique in that positive stops for an open and closed position are integrated into the heads 12, 13 of the cutter. The stops are made of the same material as the head (i.e., steel alloy) and have the same hardness as the head. The hardness is the same for all surfaces involved in stopping and there are no such pinch points near the hand while using the cutter.
Referring to
Referring to
The exemplary embodiment has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the exemplary embodiment be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
This application claims priority to application Ser. No. 61/610,632, filed on Mar. 14, 2012, the entirety of which is hereby incorporated by reference.
Number | Date | Country | |
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61610632 | Mar 2012 | US |