US3888002A - Utility knife - Google Patents

Abstract

A utility knife of the type in which the blade is slideably moved between exposed positions and a fully retracted position within an elongated handle is provided with a button head adapted to move along a recess in the handle during position adjustment of the blade and to rotate when the knife blade is in a selected latched position so that the head straddles the recess and locks the blade against further adjustment or accidental movement out of the latched position.

Description

United States Patent [191 Graham UTILITY KNIFE [75] Inventor: James Joseph Graham, Wallingford,

[ June 10, 1975 3.007144 ll/l96l Austin 30/162 3,l07,426 10/1963 Robinson........ 30/[62 3,257,67l 6/1966 Crookston 30/320 X Primary Examiner-Donald G. Kelly Assistant Examiner-J. T. Zatarga Attorney, Agent, or Firm-Prutzman, Hayes, Kalb & Chilton [57] ABSTRACT A utility knife of the type in which the blade is slide ably moved between exposed positions and a fully retracted position within an elongated handle is provided with a button head adapted to move along a recess in the handle during position adjustment of the blade and to rotate when the knife blade is in a selected latched position so that the head straddles the recess and locks the blade against further adjustment or accidental movement out of the latched position.

3 Claims, 4 Drawing Figures PATENTEDJUH 10 I575 Mi w A FIG-4 UTILITY KNIFE BACKGROUND AND SUMMARY OF THE INVENTION The present invention relates generally to utility knives and is more particularly concerned with a new and improved knife of the type in which the knife blade is slideably moved between a retracted stored position within the handle and a plurality of exposed extended positions.

A typical knife of this type is described in greater detail in U.S. Pat. No. 3,l07,426, issued to W. H. Robinson, Jr., on Oct. 22, 1963 and entitled Utility Knife. Such a knife employs a thumb manipulated blade positioning button that can be depressed to unlatch the blade and move it to any one of a plurality of selected positions. The thumb actuated button is secured to a blade carrier by means of a resilient finger that cooperates with detents in the knife handle to latch the blade at the selected position.

It has been found that utility knives of the type described can permit accidental movement of the blade during use through inadvertent or unintentional actuation of the thumb controlled position adjusting button. This is particularly true where the button is located along the top or back edge of the knife handle at a location where substantial pressure is conventionally applied during the cutting operation. Although locating the button on the side of the handle tends to reduce the incidence of unintentional movement of the blade, it does not prevent such movement and is no assurance of retention of the blade in the selected position.

Accordingly, it is an object of the present invention to provide a new and improved utility knife of the type described that includes a locking feature which prevents accidental unlatching and position change of the blade during use. Included in this object is the provision for a new and improved utility knife handle having an improved blade adjustment means for moving the knife blade into any one ofa number of selected latching positions and positively locking the blade against movement out of its latched position.

Another object of the present invention is to provide a new and improved utility knife of the type described capable of preventing unintentional depression or actuation of the slide adjusting button and thereby preventing accidental movement of the knife blade. Included in this object is the provision of a new and improved button that includes a locking feature.

Still another object of the present invention is to provide a utility knife handle of the type described that in cludes an improved blade adjusting means incorporating a swivel button adapted to move along a recess in the handle during position adjustment and to rotate when the knife blade is in a selected latched position so that the button straddles the recess and prevents further adjustment and consequent movement out of the latched position. Included in this object is the provision for a swivel button of the type described wherein the head portion thereof rotates relative to a stem portion secured to a resilient latching arm of the blade carrier.

A still further object of the present invention is to provide a new and improved utility knife ofthe type described incorporating a locking feature on the position actuating button, which feature can be easily incorporated into existing utility knife structures and is capable ofoperating in a simple and facile manner with high efficieney.

These and related objects are accomplished in accordance with the present invention by providing a knife of the type described that includes an elongated handle having a blade position adjusting recess extending longitudinally along the handle. a knife blade and a blade carrier mounting the blade for movement relative to the handle between exposed and retracted positions. The blade carrier includes a latching member movable therewith along the recess. The handle is provided with a latching surface adjacent the recess for cooperative engagement by the latching member for releasably latching the blade in one of a plurality of selected ex posed or retracted positions. The knife additionally in cludes an operating member connected to the latching member and adapted for moving the latching member out of engagement with the latching surface and for moving the blade carrier toward and away from the blade receiving slot. The operating member includes a latch lock movable along the recess during movement of the blade carrier between selected positions and adapted to rotate into a locking position when the latching member is latched. When rotated into the locking position, the latch lock cooperates with the handle to prevent unlatching of the latching member and inadvertent movement of the blade.

BRIEF DESCRIPTION OF THE DRAWING In the drawing: r

FIG. 1 is a perspective view ofa utility knife incorporating the locking feature of the present invention. the knife being in its locked position;

FIG. 2 is a side view of the utility knife of FIG. 1 partially broken away and partially in section with the locking feature in its unlocked position;

FIG. 3 is an enlarged front view of the thumb actuated button utilized in the knife of FIGS. 1 and 2', and

FIG. 4 is a side view of the button of FIG. 3 partially broken away and partially in section to illustrate the connection between the head and stem portions thereof.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring now to the drawing in greater detail wherein like reference numerals indicate like parts throughout the several figures, the present invention is shown as embodied within a utility knife 10 of the type described in greater detail in the aforementioned Robinson U.S. Pat. No. 3.IO7,426. The disclosure in that patent is incorporated herein by reference.

The utility knife 10 is comprised of an elongated handle l2 and a knife blade 14 movable between a retracted position within the handle 12 and an extended position illustrated in FIGS. 1 and 2. The handle 12 is comprised of two mating handle halves l6 and 18 joined along a longitudinally extending center line 20. A blade receiving slot or opening 22 is located at the center line 20 along the front or forward end wall 24 of the elongated handle 12 while a recessed slot 26 of larger transverse dimension extends longitudinally along the center line 20 at the top or back edge 28 of the handle 12 intermediate the ends thereof. The two mating halves l6 and 18 are secured in assembled relationship by a suitable fastener, such as the single centrally located retaining screw 30, and an exposed, thumb actuated blade positioning button, designated generally by the numeral 34, is mounted for reciprocal movement along the recessed slot 26 for controlling the adjustable positioning of the knife blade 14 between its extended and retracted positions.

Referring specifically to FIG. 2, the handle halves l6 and 18 are provided with a series of longitudinally spaced detents 36, 38 and 40 positioned along the longitudinal edge of recessed slot 26. A blade carrier 42 having a rearwardly extending resilient arm or tongue 44 is positioned within the interior of the handle 21 for slideable reciprocal movement adjacent slot 26 toward and away from the opening 22. The arm 44 has an up turned end portion or latch tab 46 adapted to be received within any one of the detents 36, 38 and 40 of the recessed slot 26. The blade positioning button 34 is secured to the resilient arm 44 adjacent tab 46 and forwardly thereof by means of a stem 48 of sufficient depth to permit the button to be depressed a sufficient distance to release the tab 46 of the resilient arm 44 from engagement with the detents and permit reciprocal travel of the blade carrier 42 longitudinally along the interior of the elongated handle 12. Thus the knife blade 14 mounted on the blade carrier 42 can be moved into and out of an extended position such as the position illustrated in FIGS. 1 and 2, or fully withdrawn into the interior of the knife handle 12 under the control of the position adjusting thumb actuated button 34.

The thumb actuated button 34 utilized in accordance with the present invention is an intercast member that consists of a generally rectangle stern portion 48 having a thickness slightly less than the transverse dimension of the recessed slot 26 within which it travels. The stem 48 tapers inwardly slightly from top to bottom and has a length or front to rear dimension of approximately three times its thickness, The free bottom end portion 50 of the stem 48 is of reduced length and in the illus trated embodiment extends through an aperture (not shown) in the arm 44 adjacent tab 46 where it is fixedly secured by convention means as such as by upsetting the projecting portion 50. As mentioned, the stem 48 may be slightly tapered toward its free end and is provided with a flat top surface 52 from which projects a centrally located inverted frusto conical spindle 54.

The intercast head 56 of the T-shaped thumb manipulated button 34 is provided with a central aperture 58 of frusto conical configuration complimentary to the spindle 54 so that the head 56 is firmly secured to the stem but is capable of free rotational movement relative thereto. The swivel head 56 is a generally rectangular planar member about twice as long as it is wide. When its longitudinal dimension is aligned with the longitudinal dimension of the recessed slot 26, the head 56 can be readily received within the recessed portion 60 of the slot as the button 34 is depressed to release the latching connection between the tab 46 and the detents located on the interior of the handle 12. However, the head 56 is too large to pass entirely through slot 26. In accordance with the present invention the head 56 is of sufficient length to extend well beyond the longitudinal edges of the recess 60 when the head is rotated so that its longitudinal dimension is extending transversely to the longitudinal direction of the slot 26. Thus, as shown in FIG. 1, the head 56 will bridge the recess 60 and prevent accidental depression of the button that might release the tab 46 from its latched position.

As best shown in FIG. 4, two transversely extending grooves 62 are cast in the flat bottom surface 64 of the button head 56 adjacent opposite longitudinal ends thereof. The grooves 62 cooperate with two heads 66 cast alongside the recessed slot on the exposed back surface 28 of the handle. As best shown in FIG. 1, the grooves 62 fit over the elongated beads 66 and cooperate therewith to provide resistance to pivotal movement of the button head 56 after it has been moved into its locked recess bridging position. Additionally, since the beads 66 are of smooth rounded configuration, and since the swivel connection between the frusto conical spindle 54 and the aperture 58 is sufficiently free to permit free movement therebetween, there is a slight upward pulling of the resilient latching tongue 44 past its neutral latching position shown in FIG. 2 as the button head is rotated into its transversely extending locking position. This provides a snap-type locking arrangement which positively indicates to the user that the button has been placed in its fully locked position and is not likely to inadvertently rotate back to the position shown in FIG. 2 where it might be accidently depressed to unlatch the blade.

As can be seen from the foregoing detailed description, the present invention provides a simple yet effective locking arrangement for a utility knife that facilitates rapid manipulation of the blade into a selected latched position and positive retention in that position. This locking feature provided an added safety dimension to the tool in that it prevents a blade position control button from being unintentionally depressed to permit accidental movement of the blade during use. The new control button of the knife can be rotated to straddle a recess in the knife handle and will snap onto beads located on each side of the recess to assure a positive locked condition. Additionally, this locking feature can be incorporated into existing knives without requiring extensive changes therein.

I claim:

I. In a knife comprising a knife blade, an elongated handle having a blade position adjusting recess extending longitudinally along the handle and an interior latching surface adjacent the recess, a blade carrier mounting the blade for slideable movement relative to the handle, said carrier including a latching member cooperating with the latching surface for releasably latching the blade in one of a plurality of selected positions, and an operating member secured to said latching member and adapted for moving the latching member out of engagement with the latching surface and for moving the blade carrier along the handle, the combination wherein said operating member includes a stem portion and an enlarged head portion rotatably mounted on the stem portion, said stern portion having a top shoulder with an integral, inverted frustoconical spindle projecting upwardly therefrom and said head having a complementary frustoconical aperture of substantially the same size, said spindle being nonreleasably positioned within said aperture with said head engaging said spindle and said top shoulder to prevent axial displacement of said head from said spindle while permitting relative rotation therebetween, said head having a width less than the width of said recess to permit movement into and along said recess during movement of the blade between selected positions and a length greater than the width of said recess, said frustoconical spindle and aperture connection permitting rotation of said head into a recess-bridging locked position only when said latching member is positioned tary ridge adapted to retainably interfit in said groove when said head is rotated into its recess-bridging position.

3. The knife of claim 2 wherein said ridge is formed on the handle and extends longitudinally along the edge of the recess and said groove is formed in the head and extends across the width thereof.

Claims (3)

1. In a knife comprising a knife blade, an elongated handle having a blade position adjusting recess extending longitudinally along the handle and an interior latching surface adjacent the recess, a blade carrier mounting the blade for slideable movement relative to the handle, said carrier including a latching member cooperating with the latching surface for releasably latching the blade in one of a plurality of selected positions, and an operating member secured to said latching member and adapted for moving the latching member out of engagement with the latching surface and for moving the blade carrier along the handle, the combination wherein said operating member includes a stem portion and an enlarged head portion rotatably mounted on the stem portion, said stem portion having a top shoulder with an integral, inverted frustoconical spindle projecting upwardly therefrom and said head having a complementary frustoconical aperture of substantially the same size, said spindle being nonreleasably positioned within said aperture with said head engaging said spindle and said top shoulder to prevent axial displacement of said head from said spindle while permitting relative rotation therebetween, said head having a width less than the width of said recess to permit movement into and along said recess during movement of the blade between selected positions and a length greater than the width of said recess, said frustoconical spindle and aperture connection permitting rotation of said head into a recess-bridging locked position only when said latching member is positioned within one of said selected latching positions, said head in its recess-bridging locked position cooperating with said handle to prevent depression of said stem and inadvertent unlatching of the latching member for movement of the blade out of its selected position.

2. The knife of claim 1 wherein one of said handle and said locking head have a groove and the other of said handle and said locking head have a complementary ridge adapted to retainably interfit in said groove when said head is rotated into its recess-bridging position.

3. The knife of claim 2 wherein said ridge is formed on the handle and extends longitudinally along the edge of the recess and said groove is formed in the head and extends across the width thereof.

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