RETRACTABLE-BLADED KNIFE

Abstract: A lightweight, slender knife (Fig. 1) having a replaceable, retractable cutting blade (28), which may be locked either in the operating or deployed position (Fig. 3a), or in a retracted or safety position (Fig. 2a), by using a single digit on one hand, is described. Safety of hospital personnel and medical waste-disposal personnel is achieved in the surgical scalpel embodiment of the present knife without loss of function or convenience of the scalpel. An automatically retracting embodiment (Fig. 6a) of the knife is also described.

Description: RETRACTA3LE-BLADED KNIFE BACKGROUND OF THE INVENTION The present invention relates generally to cutting instruments, and more particularly to surgical scalpels and other knives having retractable blades. It is well known that existing surg cal cutting implements provide a significant potential for harm to surgeons and support personnel. That is, with attention directed toward the patient, rapid handling of surgical instruments with exposed sharp edges occasionally leads to cuts and puncture wounds, and more often to loss of integrity of surgical gloves. With increasing risk of life-threatening infectious diseases, it is imperative that such risks be minimized. Utility knives having retractable blades are well known. The majority of such knives are operated utilizing actuating mechanisms located on the flat faces thereof. A relatively small number of knives having actuating mechanisms on their narrow edges are described. In U.S. Patent No. 5,207,696 for "Surgical Scalpel," which issued to Robert J. Matwijcow on Hay 4, 1993, the inventor describes a scalpel including a blade carrier and a blade shield equally movable in opposite longitudinal directions in response to longitudinal movement of an actuator along the upper edge of the scalpel housing. U.S. Patent No. 3,577,637 for "Retractable Blade Knife," which issued to Fred A. Braginets on May 4, 1971 describes an industrial blade holder combination with the blade being mounted on a carrier and selectively movable to retracted and operative positions. Extending to the rear of the blade carrier is a flexible leaf spring portion carrying a manually engageable tab or fingerpiece connected to the spring portion by a rectangular support. The leaf portion also carries a pair of upstanding latching lugs disposed to the side of the fingerpiece. Two opposed handle halves are cut away to form a longitudinally extending slot in the top edge - 2 - thereof along which the rectangular portion of the fingerpiece may move. The handle halves also have cutaway portions extending longitudinally in the top edge to form opposed recesses into which the fingerpiece may be depressed to release the latching means. A similar actuating mechanism is described in U.S. Patent. No. 4,621,425 for "Retractable Knife Handle," which issued to Carl C. Stautenberg on November 11, 1986. The blade slides described in these patents are complex and wide in order to accommodate the latching mechanisms, and consequently wide handle portions must be fabricated from more than one part in order to receive these complex si ides. Accordingly, it is an object, of the present, invention to provide slender surgical scalpels and other knives having retractable blades which may be locked in either a deployed or a retracted position. Another object of our invention is to provide slender surgical scalpels and other knives having retractable blades which may be locked in either a deployed or a retracted position and which may be operated using one digit of one hand utilizing a digit-engaging tab located on the top edge thereof. Yet another object of the invention is to provide slender surgical scalpels and other knives having retractable blades which may be locked in either a deployed or retracted position, but which cannot accidentally be deployed . Still another object of our invention is to provide slender surgical scalpels and other knives having retractable blades for which standard, commercially-available blades are employed, and which have only three parts. A further object of the invention is to provide slender surgical scalpels and other knives which are automatically retracted by depressing a finger-actuated tab on the top edge thereof. Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those s illed in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims. SUMMARY OF THE INVENTION To achieve the foregoing and other objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, the retractable-bl aded knife hereof includes a generally flat, elongated handle having a forward end and a rearward end, and further having two generally flat, parallel sides separated by a narrow top edge having an inner surface and a narrow bottom edge having an inner surface such that an elongated cavity extending substantially over the long dimension of the handle and opening to the outside at the forward end thereof is formed, the top edge having an elongated notch therethrough toward the forward end of the handle, there being formed a first indentation in the inner surface of the top edge forward of the notch and a second indentation in the inner surface of the top edge behind the notch, and the bottom edge having a notch therethrough in order to enable the second indentation in the top edge to be formed therein; a cutting blade; and a flat, elongated slide adapted to slidably move longitudinally through the cavity in the handle and adapted to receive the cutting blade, the slide member having a generally straight top edge and an opposing bottom edge, and a digit-engaging tab protruding from the top edge adapted to extend through the notch in the top edge of the handle such that the di git -engaging tab may be engaged by and actuated by a digit of the operator of the knife, the slide member having a first tab located toward the blade-receiving end thereof from the di git -engagi ng tab and adapted to engage the first indentation in the top portion of the handle, and a second tab located away from the blade-recei ing end of the slide from the di git -engaging tab and adapted to engage the second indentation in the top portion of the handle, the slide further having a resilient, deformable tang projecting from the bottom portion thereof and opposing the digi -engaging tab such that the straight top edge of he slide is forced against the inner surface of the top portion of the handle by the action of the deformable portion of the slide against the inner surface of the bottom portion of the handle. It is preferred that the blade be removable from the slide in order to permit fresh blades to be installed. Preferably, a coil spring is located within the cavity of the handle along the long dimension thereof and attached to the end of the slide away from the blade-receiving end and to the handle in the vicinity of its closed end, thereby providing a force on the slide member directed toward the rearward end of the handle which automa ically withdraws the slide from its deployed position when the di gi -engaging tab is depressed and into the handle. Benefits and advantages of the present invention include simple and inexpensive fabrication and assembly resulting from the simple, three-piece design. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and forms a part of the specification, illustrate two embodiments of the present invention and, together with the description, serve to explain the principles of the invention. Figure 1 shows a schematic representation of a side view of the scalpel embodiment, of the retractable-bl aded knife of the present invention illustrating the installation of the blade/slide assembly into the handle cavity. Figures 2a and 2b show schematic representations of a side view of the scalpel shown in Figure 1 hereof in its closed, locked position, and the top view thereof, respecti vely. Figures 3a and 3b show schematic representations of a side view of the scalpel shown in Figure 1 hereof and the top view thereof, respectively, and illustrate the blade-deployed mode thereof. Figure 4 is a schematic representation of a side view of one embodiment of the slide of the present retractable-bladed knife, and illustrates the blade/slide assembly in its pre-welded form. Figure 5 is a schematic representation of a side view of a second embodiment of the slide, and illustrates an alternative manner in which slide latching may be achieved. Figures 6a and 6b show schematic representations of side and top views, respectively, of an automatically-retracting surgical scalpel embodiment of the retractable-bladed knife of the present invention in its blade-retracted mode, and illustrate a coil spring utilized for withdrawing the slide into the handle cavity when the locking mechanism is depressed. Figures 7a and 7b show schematic representations of side and top views, respectively, of the knife shown in Figures 6a and 6b hereof in its blade-deployed condition. DETAILED DESCRIPTION OF THE INVENTION Briefly, the present invention includes a lightweight, slender cutting knife having a retractable blade which may be locked in either the operating or deployed position, or in a retracted or safety position, using a single digit on one hand. An automatically retracting embodiment thereof is also described. Reference will now be made in detail to the present, preferred embodiments of the invention, an example of which is illustrated in the accompanying drawings. Identical or similar structure is identified by the same callouts. Figure 1 shows a side schematic representation of a surgical scalpel embodiment of the retractable-bladed knife of the present invention illustrating the assembly of the three principal parts thereof. This embodiment will be used to illustrate the features of the retractable-bladed knife hereof, throughout. Handle 1^0 is generally flat and elongated in the embodiment thereof suitable for surgical procedures, among other uses. Cavity 1_2 is formed inside the handle and opens at. the front end _H thereof. Elongated slot 1_6 permits the cavity to open through the wall 1_8 of the top edge of the handle and slot 2_0 allows it to open through the wall 2_2 of the bottom edge thereof. Notches 24a and 24b are located in the inner surface of wall _1_8 > notch 24b being cut through slot _C, while notch 24a is fashioned through front end J^ . Slide J5 to which blade 8 is attached is shown with i s forward end being inserted into the handle cavity through slot. 16. Resilient, deformable tang ^_0 engages the inside of wall 1_8 once the long dimension of the slide is located parallel to the long dimension of the handle. In this manner, the slide is stably located within the cavity when the blade is in its deployed position. Resilient, deformable tang 3 , which projects below the bottom edge of slide 2_ , engages the inner surface of wall 20 and provides an upward force on the slide member to cause the upper edge _32 thereof to press firmly against the inner surface of wall _8, yet permit the slide to be readily moved within the handle cavity. A finger-engaging tab ^6 » an d latching tabs 38a and 38b are also located on the top edge ^2 of slide 26. Finger-engaging tab _3_6 protrudes through elongated slot _1_6 in the handle and may be engage by a digit of the operator of the knife to cause the slide to move within the cavity in either direction. When slide 2_6 is caused to move to its extreme forward position, wherein blade 2_8 is deployed, tab 38a and notch 24a automatically engage, as a result, of the action of tang JJ_4, and loc the slide in this position for use. When it is desired to withdraw the slide into the handle cavity, thereby completely shielding blade 28 , finger-engaging tab ^j5 is depressed. This counters the action of tang _3_4 by forcing the upper edge of the slide away from the inner surface of wall J 3, thereby releasing tab 38a from notch 24a and permitting the slide to be moved into the cavity by the operator. When the slide is moved to its extreme rearward position, tab 38b automatically engages notch 24b because of the upward action of tang 3 , thereby preventing slide 6 from accidentally moving forward. When deployment of blade 8 is desired, tab 3_6 is pressed downward by the operator, thereby releasing tab 38b from notch 24b against the action of tang 3_4 » and slide 2 may be moved forward in the handle cavity. Slide 6 may be removed from the handle cavity for replacement, when blade 2B becomes dull or otherwise unsuitable for use, by depressing tang _3_ through slot 2_2 in handle 10. Figures 2a and 2b show schematic representations of side and top views, respectively, of the subject, scalpel in its closed, locked position. Figures 3a and 3b show schematic representations of a side view and top view, respectively, of the scalpel and illustrate its blade-deployed, or open, locked position. Slots ^0 and 4_2, along with slots l ό_ and ^_0, and front-end opening _1_ per it handle H) to be molded in one process step with cavity \ 2_ and indentations or notches 24a and 24b in pi ace. Figure 4 is a schematic representation of a side view of one embodiment of the slide and illustrates the blade/slide assembly in its pre-welded form. Shown is slide 2_6 having been molded in two attached sections, 26a and 26b , with blade 2_8 subsequently being installed on one of the sections. The two sections are then folded together and welded, thereby rigidly capturing blade 2_8 as slide/blade assembly ^4. If it is now desired to change blades, slide/blade assembly 4_4 is removed from the handle, and discarded, being replaced by a new slide/blade assembly . Figure 5 is a schematic representa ion of the side view of a second embodiment of slide 2_6. Slot j> permits the automatic, reversible engaging of latching tabs 38a and 38b with notches 24a and 24b , respectively, when slide 6 is moved to its forward or rearward positions in handle 10 , respect vely. When finger-engaging tab 3_6 is depressed, the latching action is released, since slide 6 is deformable as a result of the placement of slot 46. Figures 6a and 6b are schematic representations of side and top views, respectively, of an automatically-retracting embodiment of the retractable-bladed surgical scalpel of the present invention in its blade-retracted condition, and illustrate coil spring 4_8, stretched between slide ^6 and the rearward interior of handle 1_0, being utilized for withdrawing the slide into the handle cavity when finger-engaging tab 3_6 is depressed. Slide ^6 is adapted 50 to receive coil spring 4_8, such that a longer spring may be utilized in order to prevent the elastic limit thereof being exceeded. Figures 7a and 7b are schematic representations of side and top views, respectively, of the automatically-retracting embodiment of the present invention shown in Figures 6a and 6b hereof, in its blade-deployed condition. The lower wall ^ of slide 2_6 is relieved _5_2 such that, when finger-engaging tab _3_6 is depressed, slide 2_6 will automatically move rearward with a speed which permits latching tab 38b to engage notch 24b in handle _1_0, thereby preventing blade 2_8 from moving forward if the surgical scalpel is accidentally dropped. Raised portion _5_4 in in the lower surface of slide ^6 assists in stabilizing slide 6 in both its forward and rearward latched positions. Spring _4S may be attached to the rear of handle J ) at point _5_5 through slot 4_2, once slide 2_6 is installed into the cavity thereof. The foregoing description of two preferred embodiments of the invention have been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. For example, it would be apparent, to one having skill in the surgical arts, after carefully studying the present disclosure, that various handle shapes and sizes and numerous cutting blade designs may be utilized in the present, invention. Additionally, choice of materials would depend on the intended use; for example, biocompatible and sterilizable materials would be utilized for surgical instrument embodiments of the invention. The embodiments were chosen and described in order to best, explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto.

Claims: O 96/11637 PC17US95/13026 - 1 0 - WHAT IS CLAIMED IS 1. A knife having a retractable blade, comprising in combination: a. a generally flat, elongated handle member having a forward end and a rearward end, and further having two generally flat, parallel sides separated by a narrow top portion having an inner surface and a narrow bottom portion having an inner surface such that an elongated cavity extending substantially over the long dimension of said handle member and opening to the outside at the forward end thereof is formed, the top portion having an elongated notch therethrough toward the forward end of said handle member, there being formed a first indentation in the inner surface of the top member forward of the notch and a second indentation in the inner surface of the top member behind the notch, and the bottom member having a notch therethrough in order to enable the second indentation in the top member to be formed therein; b. a cutting blade; and c. a flat, elongated slide member adapted to slidably move longitudinally through the cavity in said handle member and adapted to receive said cutting blade, said slide member having a generally straight top portion along the narrow dimension thereof and an opposing bottom portion, and a digit-engaging tab protruding from the top portion adapted to extend through the notch in the top portion of said handle member such that the digit-engaging tab may be engaged by and actuated by a digit of the operator of said knife, said slide member having a first tab located toward the blade-receiving end of said slide member from the digit-engaging tab and adapted to engage the first indentation in the top portion of said handle member, and a second tab located away from the blade-receiving end of said slide member from the digit-engaging tab and adapted to engage the second indentation in the top portion of said handle member, said slide member further having a resilient, deformable tang projecting from the bottom portion thereof and opposing the digit-engaging portion thereof such that, the straight, top portion of said slide member is forced against, the inner surface of the top portion of said handle member by the action of the deformable tang of said slide member against the inner surface of the bottom portion of said handle member. 2. The knife as described in Claim 1, wherein said slide member is adapted to removably receive said cutting blade. 3. A knife having a retractable blade, comprising in combination: a. a generally flat, elongated handle member having a forward end and a rearward end, and further having two generally flat, parallel sides separated by a narrow top portion having an inner surface and a narrow bottom portion having an inner surface such that an elongated cavity extending substantially over the long dimension of said handle member and opening to the outside at the forward end O 96/11637 P -12- thereof is formed, the top portion having an elongated notch therethrough toward the forward end of said handle member, there being formed a first indentation in the inner surface of the top member forward of the notch and a second indentation in the inner surface of the top member behind the notch, and the bottom member having a notch therethrough in order to enable the second indentation in the top member to be formed therein; b. a cutting blade; c. a flat, elongated slide member adapted to slidably move longitudinally through the cavity in said handle member and adapted to receive said cutting blade, said slide member having a generally straight top portion along the narrow dimension thereof and an opposing bottom portion, and a digit-engaging tab protruding from the top portion adapted to extend through the notch in the top portion of said handle member such that the digit-engaging tab may be engaged by and actuated by a digit of the operator of said knife, said slide member having a first, tab located toward the blade-receiving end of said slide member from the digit-engaging portion and adapted to engage the first. indentation in the top portion of said handle member, and a second tab located away from the blade-receiving end of said slide member from the digit-engaging tab and adapted to engage the second indentation in the top portion of said handle member, said slide member further having a resilient, deformable tang projecting from the bottom portion thereof and opposing the digit-engaging tab such that, the straight top portion of said slide member is forced against the inner surface of the top portion of said handle member by the action of the deformable tang against the inner surface of the bottom portion of said handle member; and d. coil spring means located within the cavity of said handle member disposed generally along the long dimension -13- thereof and adapted to engage said slide member in the vicinity of the end thereof away from the blade-receiving end and said handle member in the vicinity of the closed end thereof, thereby providing a force on said slide member directed toward the rearward end of said handle member. 4. The knife as described in Claim 3, wherein said slide member is adapted to removably receive said cutting blade.

Inventors: PLATTS DAVID, PLATTS, DAVID
Applicants: INNOVATIVE SURGICAL TECHNOLOGY, PLATTS DAVID, INNOVATIVE SURGICAL TECHNOLOGY, INC. (IST), PLATTS, DAVID
Application year: 1995
Main classification: A61B17
IPC codes: A61B17