The invention relates generally to the field of hand tools.
Hand tools such as conventional pliers, bolt cutters, and cutting pliers are used for various tasks involving gripping, cutting, and clamping. Such tools typically consist of two levers that work in opposite directions with a fulcrum at the point where the levels rotate (i.e. both levers are first-class levers). The basic mechanical principle underlying such tools is that exerting force on the handles of a pair of pliers multiplies the force several times when it is exerted on the load. These basic are well adapted for common tasks and are in common use. However, there are applications in which it can be useful to multiply the force beyond the range made feasible by the simple levers associated with such tools. One such application is the cutting of a ring that has become too tight on a finger to be removed by slipping the ring off the finger. Rings are often too thick to permit cutting with simple lever-based tools. Likewise, the adoption of hard metals such as titanium, tungsten carbide, and platinum as materials for rings makes such rings very difficult to cut through.
Rings can become tight on a finger when an injury such as a fracture causes the adjacent tissue to swell. This can be very painful to the person wearing the ring and can restrict circulation, obstruct lymphatic drainage, and lead to additional swelling. There are various techniques for removing rings from injured fingers. In some cases, lubrication with soap and water is enough to permit twisting the ring off the finger. If the ring is too tight or the wearer is too much pain, a conventional ring cutter can be used to cut through a narrow ring band. Such cutters consist of a lever that slides a protective cutting plate under the ring while a miniature circular saw blade is lightly pressed onto the outer portion of the ring and rotated to saw through the ring band. Once the cut has been made, the ring may be bent apart and removed. Another technique is to use a high speed rotary tool with a sharp-edged grinder attachment in conjunction with a heat-resistant shield between the skin and ring. The increasing popularity of rings made from hard metals such a platinum and titanium, have made ring removal a more difficult task. For example, it can take several minutes to remove a ring made of platinum or titanium using a conventional ring cutter. Furthermore, rings made of tungsten carbide can be extremely difficult, if not impossible to cut. Such rings are typically removed by using locking pliers or a hammer to induce the ring to crack. Such methods lack precision and expose the person wearing the ring to further injury. Therefore, there is a need in the field for a tool that operates quickly and effectively to cut and remove rings of any type.
The invention comprises a hand tool in the general configuration of pliers having gripping jaws or cutting edges. The invention can be used for gripping, clamping, or cutting objects. A critical feature of the tool is the use of force multipliers to transfer force from a hand lever to a gear reduction hub that is connected to one of the jaws. Force multipliers are devices that are able to provide greater output force than input force. Examples of force multipliers include levers, pulleys, screws, gears, and hydraulic pistons that are configured to increase output force.
For example, the preferred embodiment of the tool is a ratcheting cutter has force multipliers working together to produce sufficient torque to cut through any metal, including titanium. This kind of tool can readily be configured such that 52 lb-ft of torque at the handle will produce over 100,000 lb-ft of torque at the cutting head in a smooth and continuous progression of applied force. This cutting device can be used in a variety of fields, but is particularly suited for use as a ring cutter. In addition, such a tool can cut through fencing, pad locks, cable, and bolts. With a different head design, the tool can be used for gripping and clamping onto various surfaces.
The preferred embodiment of the tool is configured in the general form of a hand tool having a pair of handles of which the lower handle acts as a lever, being joined to a double fulcrum force multiplier that is connected to an engagement pawl. By applying force to the lower lever it substantially increases the force applied to a pawl, which in turn rotates a gear hub which acts as another force multiplier. By pushing a detentable button at top of tool, a slide will move down the back of cam release slide and cause a locking pawl to engage the hub. When the locking pawl is engaged, a spring in the pawl ejects the pawl from gears and allows the gear hub to rotate forward in a ratcheting manner as the handles are repeated squeezed together and released. This causes the upper jaw at the opposing end to advance towards the lower jaw in a controlled manner for clamping or cutting. When finished, the user may push the detentable button on the top of the tool to a different position, thus causing the slide to disengage the locking pawl from the gear hub, thus allowing the tool to return to a reset position.
The tool can also be made using other combinations of force multipliers to apply force to a gear reduction hub. For example, in another embodiment, the lower handle can be squeezed to drive a bar having a pawl at its end into the teeth of gear which in turn drives the gear reduction hub to rotate in a forward direction.
The preferred embodiment of the hand tool 1 is shown in
A gear reduction hub 11 is attached to the base assembly by a pin 18 about which it pivots. The gear reduction hub 11 has a geared face 22 with teeth that are configured to engage with the toothed face 21 of the advancing pawl. When the lower handle 3 is squeezed towards the upper handle of the base member 2, the engagement of the advancing pawl with the geared face 21 creates an additional mechanical advantage causing the gear reduction hub 11 to pivot about pin 18 and thus moving the upper jaw 12 of the tool towards the lower jaw 13. The amount of throw in the movement of the assembly of the lower handle 3, connecting lever 7, and advancing pawl 10 is fairly short, and thus a user will generally need to squeeze the lower handle 3 towards the upper handle 25 several times to cause the upper jaw 12 to move from a fully open position to a closed position in which the upper jaw touches the lower jaw 13.
Retrocession of the gear reduction hub 11 during advancement is prevented by engagement of a locking pawl 14 with the geared face 22 of the gear reduction hub 11. This ensures a continuous application of force by the upper jaw 12 as the tools clamps or cuts material. A compression slide 15 is pivotably attached to the locking pawl at one end and to a release button 17 at the other end, which fits over a slot 20 in the base member 2. A spring 24 maintains a bias force on the locking pawl to keep it pressed against the gear face as the gear reduction hub 11 is advanced towards a closed position.
A bar 16 pivotally connects the middle of the compression slide 15 to a hole or slot 19 in the gear reduction hub 11. By pushing the release button 17 forward, the compression slide forces the locking pawl 14 to engage the geared face. Pushing downward on the release button 17 forces the compression slide to push down on the base of the locking pawl 14, thus causing it to disengage from the gear face 22. The disengagement is made easier if the lower handle 3 is squeezed lightly while depressing the release button 17. Pulling backward on the release button 17 causes the bar 16 to pull the gear reduction hub 11 to the open position and thus resets the upper jaw 12 to its starting position.
The tool 1 can be fitted with different kinds of jaws 12 and 13 depending on the intended function of the tool 1. For example, as shown on
An alternate embodiment of the hand tool 101 is shown in
A pin 108 pivotably attaches the gear reduction hub 111 to the base member 2. The gear face 112 may extend past the bottom edge of the gear reduction hub 111 so that the gear reduction hub 111 does not interfere with the spring hinge 105. The upper jaw 116 may be an integral part of the gear reduction hub 111 or may be selectively detachable by putting a attachment point (not shown) in the region 118 that will not interfere with the base assembly member. In general, it is preferred that an attachment point not be located in an the area 115 where the attachment point might so interfere.
The advancing gear 109 is engaged with the gear face 112 on the gear reduction hub 111. When the lower handle 3 is squeezed towards the upper handle 107, the advancing bar 104 engages the advancing gear 109 and exerts a mechanical advantage while gear face 113 of the advancing gear 109 simultaneously engages the gear face 112 of the gear reduction hub 111 thus causing the gear reduction hub 111 to pivot about pin 108 and causing the upper jaw 116 to move towards the lower jaw 117. The radius length of the advancing gear 109 will determine both the extent of advancement of the gear reduction hub 111 when the lower handle 2 is squeezed as well as the magnitude of the mechanical advantage. A user will generally need to squeeze the lower handle 3 towards the upper handle 107 several times to cause the upper jaw 116 to move from an open position to a closed position in which the upper jaw touches the lower jaw 117.
The gear reduction hub 111 is prevented from receding during advancement by engagement of a locking pawl 121 with the advancing gear 109. The locking pawl 121 engages with the gear face 113 of the advancing gear 109. The locking pawl 121 can be selectively released and engaged from the advancing gear 109 by pushing a release button 110 forward and backward in the slot 120 in the base assembly 2.
Although the invention has been described with reference to a particular arrangement of parts, features, and the like, these are not intended to exhaust all possible arrangements or features, and indeed many other modifications and variations will be ascertainable to those of skill in the art.
This application claims the benefit of provisional application 62/081,376 which was filed on Nov. 18, 2014.
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8286461 | Hofmann | Oct 2012 | B2 |
8407875 | Gray | Apr 2013 | B2 |
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20130014618 | Wu | Jan 2013 | A1 |
Entry |
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Klein Tools, Inc, PVC Cutter 50500 Parts Breakout, Klein Tools, Inc., Lincolnshire, IL 60069-1418. |
Number | Date | Country | |
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62081376 | Nov 2014 | US |