Patent Grant
9724835
Not applicable.
Not applicable.
Not applicable.
1. Field of the Invention
The present invention relates generally to the field of cutting shears, and more specifically, to cutting shears with a longitudinally slidable and preferably rotatable thumb ring that moves ergonomically with the thumb during use.
2. Description of the Related Art
There are a number of cutting shears incorporating longitudinally and/or rotationally adjustable thumb and finger rings that are the subject of issued patents or published patent applications, but none of these inventions includes the novel features of the present invention, most notable a thumb ring that is readily slidable back and forth in the longitudinal direction and readily pivotable for a comfortable thumb angle during use of the scissors, while in addition, the thumb ring is automatically restrained in its last position when the thumb is temporarily removed from the ring.
U.S. Pat. No. 1,479,908 (Goshia, 1924) discloses scissors with an automatically adjustable thumb ring that is connected to the shank of the scissors via a rivet pin fitted with a friction roller. The thumb ring is designed to slide forward and backward on the shank (i.e., the handle) with each opening and closing of the scissors. The thumb ring may be optionally locked in place with a set screw. There is no provision in this invention for automatic restraint of the ring when the thumb is removed from the ring.
U.S. Pat. No. 2,158,277 (Dolph, 1939) provides scissors with a manually adjustable thumb ring, which may be set to any one of a number of discreet positions along the shaft. The discreet positions are determined by a set of teeth along the shaft that mate with a set of matching teeth on the thumb ring.
U.S. Pat. No. 2,571,675 (Bray, 1951) describes scissors with removable thumb and finger rings, in which the thumb ring may be longitudinally adjusted and locked into position prior to use, and in which the diameters of the thumb and finger rings may be adjusted to fit hands of various sizes.
U.S. Pat. No. 4,642,895 (Gauvry, 1987) discloses scissors having a thumb loop that is rotatable longitudinally along and perpendicularly around the axis of the scissors handle by means of a ball and socket interconnection. The invention also comprises a rubber stop or bumper to limit the closing of the blades. In this invention, the thumb loop does not slide freely along the longitudinal axis of the handle; instead, it only rotates around the ball and socket joint.
U.S. Pat. No. 5,469,624 (Benton et al.) provides scissors and similar instruments that comprise interchangeable, rotatable and pivotable thumb and finger rings that incorporate a hand-adjustable tensioning means. The rings are not capable of sliding longitudinally along the handle.
U.S. Pat. No. 6,212,780 (Huang, 2001) describes scissors and similar instruments that comprise a thumb ring that may be adjusted longitudinally along the handle and set a discrete points prior to use, using a cam lock or screw as a locking means.
U.S. Pat. No. 6,249,977 (Knopp, 2001) discloses scissors having a T-shaped finger grip and a thumb ring grip, in which each of the two grips can be adjusted longitudinally along a handle and secured at the desired position with a locking screw.
U.S. Pat. No. 6,915,578 (Yusufov et al., 2005) and U.S. Patent Application Publ No. 2004/0211068 (Yusufov et al, 2004) provide a reversible-blade scissors comprising finger and thumb rings that are longitudinally and pivotable adjustable. Each ring is secured both longitudinally and pivotably by a single thumb screw prior to use of the scissors. The shafts of the thumbs screws are fitted into longitudinal slots, (i.e., tracks), in which the tracks are within flat sides of the handles, and the flat sides of the handles are in the same plane as the flat sides of the blades.
U.S. Pat. No. 7,424,778 (Benton, 2008) and U.S. Patent Application Pub. No. 2005/0204569 (Benton, 2005) describe scissors having a pivotable adjustable thumb ring, wherein the pivot shaft is made of flexible material, thereby allowing the ring to flex as well as pivot. There is no longitudinal adjustment of the thumb ring in this invention.
U.S. Pat. No. 7,966,733 (Jun, 2011) and U.S. Patent Application Pub. No. 2008/0172886 (Jun, 2008) disclose scissors comprising a thumb ring that is capable of rotating in two independent directions and pivoting around one axis that is parallel to the handle. The thumb ring of this invention is not capable of longitudinal adjustment.
U.S. Patent Application Pub. No. US 2006/0010695 (Wu, 2006) provides thumb and finger rings for scissors that are rotatable and detachable. There is no provision for longitudinal adjustment of the rings in this invention.
U.S. Patent Application Pub. No. US 2010/0192384 (Fox, 2010) describes shears having a pivotable and flexible finger ring. There is no provision for longitudinal adjustment of the ring in this invention.
U.S. Patent Application Pub. No. US 2010/0212165 (Parnazzina et al., 2010) discloses scissors with a pivotable thumb ring and saw-toothed edges on the blades. There is no provision for longitudinal thumb ring adjustment in this invention.
U.S. Patent Application Pub. No. US 2010/0242289 (Roskam et al., 2010) provides scissors comprising an articulated thumb ring that is magnetically attached to the handle. The thumb ring may be detached and reattached to the handle during use of the scissors without removing the ring from the thumb.
U.S. Patent Application Pub. No. US 2011/0016728 describes a scissors with thumb ring that is adjustable for offset, rotation, and diameter. There is no provision for longitudinal adjustment of the thumb ring in this invention.
U.S. Pat. No. D536,941 (Nenadich et al, 2007), D537,312 (Nenadich et al., 2007), and U.S. Design Pat. No. D538,612 (Nenadich et al, 2007) illustrate scissors having pivotable (but not longitudinally adjustable) thumb rings.
The present invention is a pair of scissors comprising: a first cutting blade comprising a thumb handle and a thumb ring; a second cutting blade comprising a finger ring, wherein the second cutting blade is pivotally attached to the first cutting blade, and wherein the first and second cutting blades pivot relative to one another within a first plane that is defined by a first axis and a second axis; wherein the thumb ring is slidably attached to the first cutting blade by a shaft that moves freely but with a certain amount of friction along a longitudinal slot in the thumb handle of the first cutting blade when the scissors are in use; and wherein the longitudinal slot in the thumb handle is situated within a second plane that is defined by the first axis and a third axis that is perpendicular to the first and second axes so that the second plane is perpendicular to the first plane.
In a preferred embodiment, the invention further comprises a tensioning washer, a lower slide washer, and an upper slide washer; wherein the thumb handle comprises an upper surface and a lower surface; wherein the tensioning washer is situated between the thumb ring and the lower slide washer, the lower slide washer is situated between the tensioning washer and the lower surface of the thumb handle, and the upper slide washer is situated adjacent to the upper surface of the thumb handle directly above the longitudinal slot; wherein the shaft extends through the upper slide washer, the longitudinal slot in the thumb handle, the lower slide washer, and the tensioning washer; and wherein the shaft is connected to the thumb ring.
In an alternate embodiment, the invention further comprises a micro thrust bearing and an upper slide washer; wherein the thumb handle comprises an upper surface and lower surface; wherein the micro thrust bearing is situated between the thumb ring and the lower surface of the thumb handle, and the upper slide washer is situated adjacent to the upper surface of the thumb handle directly above the longitudinal slot; wherein the shaft extends through the upper slide washer, the longitudinal slot in the thumb handle, and the micro thrust bearing; and wherein the shaft is connected to the thumb ring.
In yet another alternate embodiment, the invention further comprises a magnet, a lower slide washer and an upper slide washer; wherein the thumb handle comprises an upper surface and a lower surface; wherein the magnet is situated between the thumb ring and the lower slide washer, the lower slide washer is situated between the magnet and the lower surface of the thumb handle, and the upper slide washer is situated adjacent to the upper surface of the thumb handle directly above the longitudinal slot; wherein the shaft extends through the upper slide washer, the longitudinal slot in the thumb handle, the lower slide washer, and the magnet; and wherein the shaft is connected to the thumb ring.
In a preferred embodiment, the thumb ring rotates relative to the longitudinal slot. In an alternate embodiment, the shaft comprises a square portion that is configured to fit within the longitudinal slot in the thumb ring and that prevents the thumb ring from rotating relative to the longitudinal slot. In yet another alternate embodiment, the invention is a pair of scissors comprising; a first cutting blade comprising a thumb handle and a thumb ring; and a second cutting blade comprising a finger ring, wherein the second cutting blade is pivotally attached to the first cutting blade; wherein the thumb ring is slidable attached to the first cutting blade by a shaft that moves freely but with a certain amount of friction along a longitudinal slot in the thumb handle of the first cutting blade when the scissors are in use; and wherein each of the first and second cutting blades comprises two flat sides, that thumb handle comprises two sliding surfaces, and the sliding surfaces of the thumb handle are perpendicular to the flat sides of the cutting blades.
The present invention is cutting shears or scissors that incorporate a multiply adjustable thumb ring. As used herein, the terms “shear,” “cutting shears” and “scissors” are used interchangeably. Modes of adjustment of the thumb ring include adjustment of the longitudinal position of the thumb ring along the length of the handle and adjustment of the angular orientation of the thumb ring around an axis that is perpendicular to the long axis of the handle. Each mode of adjustment can be accomplished with the cutting hand without removing the thumb from the thumb ring or the finger from the finger ring. The ability to adjust the scissors as needed for a particular cutting operation and to adjust the scissors to fit the user's hand size and shape is important for reducing fatigue and for minimizing repetitive-motion injuries.
The ability to quickly and easily slide the thumb ring longitudinally along the sliding surfaces (i.e., the upper and lower surfaces) of the thumb handle is particularly useful for cutting hair. For example, when the thumb ring is slid forward (toward the blades), the cutting strokes are more precise, which is useful for making delicate and high-precision cuts around the eyes and ears. Conversely, when the thumb ring is slid rearward, more force can be applied to the blades, which is useful for making fast cuts on non-critical areas, such as initial cropping of long hair. During haircutting, the hairdresser or barber typically switches from using scissors to using a comb multiple times; therefore, it is highly beneficial for the scissors thumb ring to remain in place when the thumb is temporarily removed from the ring for combing, etc. because the thumb can then be easily reinserted into the ring without minimal loss of time or energy. In a similar manner, it is beneficial for the rotational position of the thumb ring to remain fixed when the thumb is temporarily removed from the ring. The present invention is superior to the prior art because the adjustments of the thumb ring are easily and quickly made with the user's thumb and finger inserted into the rings of the scissors handles, and the adjustments maintain their positions until they are purposely readjusted. None of the inventions of the prior art has this capability.
The materials and design of the present invention are purposely optimized to provide low friction when longitudinal or rotational adjustments are desired, but they also provide adequate friction to hold the desired position of the thumb ring when movement is not desired. There are three major embodiments of the present invention. Different thumb ring assembly components are used in each of the three embodiments to provide controlled friction for the adjustable thumb ring. All of the embodiments comprise identical handles in which the sliding surfaces of the thumb handle are perpendicular to the flat sides of the scissors blades. Each thumb handles incorporates a longitudinal slot through which the thumb ring components are attached. The present invention may be used in combination with most types of conventional scissors by installing a slot in the thumb handle of the scissors. The slot provided a track for the moving components. The sliding surfaces of the thumb handle are highly polished to eliminate undesired friction.
In the first embodiment, the thumb ring is attached to the handle by a screw that passes through the handle slot. (As used in the claims, the term “shaft” is intended to encompass the shaft of a screw.) Several washers are mounted on the screw. These washers include low-friction slide washers installed on each side of the handle and in contact with the polished faces of the handle, one rubber tensioning washer and standard metal washers in contact with the thumb ring and the underside of the screw head. The slide washers are preferably made of polytetrafluoroethylene (PTFE; e.g., trade name TEFLON™), plastic or other slide-enhancing materials. The tensioning washer is preferably made of a compressible synthetic rubber such as neoprene or nitrile having durometer hardness in the range of about 40 A to 80 A. The tensioning washer preferably has an uncompressed thickness of about 0.1 to 0.2 inch. During assembly, the screw is threaded into a threaded hold in the base of the thumb ring until the tensioning washer is compressed sufficiently to provided proper sliding and rotational friction for the thumb ring.
The second embodiment is similar to the first embodiment, except that the lower slide washer and tensioning washer of the first embodiment are replaced with a micro thrust bearing. The thrust bearing provides a very low-friction contact with the outside surface of the handle, while the required friction for the assembly is supplied by the slide washer in contact with the inside surface of the handle. The micro thrust bearing may be any suitable commercial product, such as part number 6655K12 from McMaster-Carr Supply Company of Aurora, Ohio. The latter part has steel ball bearings and an outside diameter of 0.5 inch, although the present invention is not limited to any particular outside diameter of the micro thrust bearing. The micro thrust bearing a preferably comprised of a ring in which ball bearings are embedded. The ring of the micro thrust bearing may be comprised of any suitable material, for example, plastic or nylon, and the ball bearings may be comprised of any suitable material, for example, steel or ceramic.
The third embodiment is similar to the first embodiment except that the tensioning washer is replaced by a cylindrical magnet. In this embodiment, friction between the outside slide washer and the contact surface of the handle is provided by a compression force resulting from the magnetic attraction between the magnet and the handle. For the third embodiment, the handle must be made of a metal material, such as stainless steel or chrome-plated carbon steel, that attracts magnets. Rare earth magnets, which have strong magnetic field compared to iron magnets of the same size, are preferable for this invention because they are lighter and smaller than comparable-strength iron magnets.
It is possible to combine the features of two or more of the three embodiments to form a hybrid configuration. For example, the thumb ring assembly may comprise a micro thrust bearing (from the second embodiment) on one or both contact surfaced of the thumb handle in combination with a magnet (from the third embodiment) on one side of the handle.
The present invention preferably incorporates a polymer bumper mounted on the inner surface of one handle. This bumper contacts the inner surface of the opposing handle when the scissors are fully closed. The purpose of the bumper is to set the position of the blades relative to each other when the scissors are fully closed and to minimize wear that would otherwise occur if the hard inner surfaces of the handles came into direct contact during closing of the scissors. The bumper may optionally be placed either forward of the thumb ring (i.e., closer to the blades) or rearward of the thumb ring. Each of the embodiments of the present invention will operate correctly with either a forward-mounted or rearward-mounted bumper.
Each of the three embodiments comprises a threaded shaft that passes through the slot of the thumb handle and slides back and forth within the slot to provide longitudinal adjustment of the thumb ring. The threaded shaft may optionally be manufactured either as an integral piece of the ring component, or alternately, it may be a separate screw component or non-integral threaded shaft that threads into the ring component. The configuration of the threaded shaft (integral threaded shaft, non-integral threaded shaft or separate screw) does not affect the operation of the invention.
Each of the three embodiments may optionally comprise a threaded shaft with a square (non-threaded) center portion in lieu of a fully threaded shaft. The purpose of the square portion is to prevent rotational movement of the thumb ring. In this configuration, the angle of the thumb ring is preset and locked into position prior to use, while longitudinal movement is still permitted. The fixed rotational option may be preferred by some users. This embodiment is shown in
The compression of the tensioning washer 15 is increased by tightening the screw 19 until the resistance of the thumb ring 4 against rotational and longitudinal movement is at the correct level. The arrow 20 shown in
As shown in
Although this first and second embodiments are shown with a screw 19, and the third embodiment is shown with an integral threaded shaft 26, any of the three embodiments could be made with a non-integral threaded shaft (similar to be partially threaded shaft 31 and nut 29 shown in
As shown in
Although the preferred embodiment of the present invention has been shown and described, it will be apparent to those skilled in the art that many changes and modifications may be made without departing from the invention in its broader aspects. The appended claims are therefore intended to cover all such changes and modifications as fall within the true spirit and scope of the invention.
This application is a continuation of co-pending U.S. patent application Ser. No. 13/526,977, filed Jun. 19, 2012 which claims the benefits of U.S. Provisional Application No. 61/572,884, filed Jul. 25, 2011, the disclosures of which are hereby incorporated by reference in their entirety including all figures, tables and drawings.
| Number | Name | Date | Kind |
|---|---|---|---|
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| 430677 | Pearsall | Jun 1890 | A |
| 590330 | Nolen | Sep 1897 | A |
| 753919 | Rowe | Mar 1904 | A |
| 927058 | Krouse | Jul 1909 | A |
| 1479908 | Goshia | Jan 1924 | A |
| 2158277 | Dolph | May 1939 | A |
| 2571675 | Bray | Oct 1951 | A |
| 2744324 | Chuba | May 1956 | A |
| 2893347 | Freiberg | Jul 1959 | A |
| 4642895 | Gauvry | Feb 1987 | A |
| 4742617 | Gauvry | May 1988 | A |
| 5060381 | Taberlet | Oct 1991 | A |
| 5469624 | Brenton et al. | Nov 1995 | A |
| 6212780 | Huang | Apr 2001 | B1 |
| 6249977 | Knoop | Jun 2001 | B1 |
| 6915578 | Yusufov et al. | Jul 2005 | B2 |
| D536941 | Nenadich et al. | Feb 2007 | S |
| D537312 | Nenadich et al. | Feb 2007 | S |
| D538612 | Nenadich et al. | Mar 2007 | S |
| 7424778 | Brenton | Sep 2008 | B2 |
| 7966733 | Jun | Jun 2011 | B2 |
| 20040211068 | Yusufov et al. | Oct 2004 | A1 |
| 20050204569 | Brenton | Sep 2005 | A1 |
| 20060010695 | Wu | Jan 2006 | A1 |
| 20060064879 | Lauritzen et al. | Mar 2006 | A1 |
| 20080172886 | Jun | Jul 2008 | A1 |
| 20100192384 | Fox | Aug 2010 | A1 |
| 20100212165 | Parnazzini et al. | Aug 2010 | A1 |
| 20100242289 | Roskam et al. | Sep 2010 | A1 |
| 20110016728 | Hann et al. | Jan 2011 | A1 |
| Number | Date | Country |
|---|---|---|
| 1370758 | Apr 1972 | GB |
| Number | Date | Country | |
|---|---|---|---|
| 20160318197 A1 | Nov 2016 | US |
| Number | Date | Country | |
|---|---|---|---|
| 61572884 | Jul 2011 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13526977 | Jun 2012 | US |
| Child | 15210614 | US |
