US3337954A

US3337954A - Electric driving unit for operating a knife or the like

Info

Publication number: US3337954A
Application number: US496947A
Authority: US
Inventors: Russell O Robison
Original assignee: Dominion Electric Corp
Current assignee: Dominion Electric Corp
Priority date: 1965-10-18
Filing date: 1965-10-18
Publication date: 1967-08-29
Anticipated expiration: 1984-08-29

Description

R. O. ROBISON Aug. 29, 1967 ELECTRIC DRIVING UNIT FOR OPERATING A KNIFE OR THE LIKE Filed Oct. 18, 1965 2 Sheets-Sheet 1 D llllllll Il Aug. 29, 1967 R. o. ROBISON' ELECTRIC DRIVING UNIT FOR OPERATING A KNIFE OR THE LIKE Filed OCt. 18, 1965 2 Sheets-Sheet 2 `mvENToR RUSSELL 0. H05/SON BY Wf- ,/l /mw w75# United States Patent O 3,337,954 ELECTRIC DRIVING UNIT FOR OPERATING A KNIFE OR THE LIKE Russell O. Robison, Plymouth, Ohio, assignor to Dominion Electric Corporation, a corporation of Ohio Filed Oct. 18, 1965, Ser. No. 496,947 12 claims. (cl. 30-272) ABSTRACT OF 'IHE DISCLOSURE An electric knife having blade-holding members alternately reciprocal in opposite directions -by cam members rotatable in openings in the members, the blade-holding members including spring lbiased locking pins cooperative with blades inserted -in the members to lock the blades to the members, releasing means positioned to simultaneously release the locking pins from both 'blades, and switch means for controlling the electrical energization of the knife motor, the switch means having two Contact elements the one par-t movable toward and away from the other part for normal operation of the switch and the other part Abeing movable away from the one part upon movement of the releasing means to unlock the locking pins and upon being moved away from the other switch part rendering the switch means inoperative and preventing energization of the motor.

My invention relates to electric driving units for operating devices such as reciprocating knife blades and the like.

An object of my invention is to provide an improved driving mechanism so constructed and arranged as to produce improved characteristics in operation.

Another object is the provision of a unique structure and arrangement for the reciprocation of knife blades or the like Iby an electrically powered mechanism.

Another object is the provision for an improved switch mechanism for such a driving unit with more assured and safe operation.

Another object is the provision of a unique arrangement of a safety switch controlling the electrical energization of a motor in such a driving unit and a locking mechanism for locking knife blades to the unit so that the knife blades cannot be `disengaged without de-energization of the motor in the unit.

Another object is the provision of a novel arrangement for requiring the de-energization of an electrical driving unit before reciprocating members may be disengaged from the unit.

Another object is the provision of improved elements for coupling knife blades to the driving' mechanism in an electrical .power unit.

Another object is the provision of an integra-l coupling element so arranged as to provide a direct connection -between a revolving cam and the shank of a knife blade, which element is self-lubricating for Ibetter bearing and sliding action. Y Another object is the provision of a coupling element for coupling a knife blade with a revolving cam, which is molded nylon, Teon or the like, or a lubricant-impregnated material, providing superior bearing and sliding action.

Another object is the provision of a coupling element having a spring-biased boss formed in the wall thereof to aid in the firm holding of the shank of the knife blade or the like.

Another object is the provision of the construction of a battery assembly -in which leaf-type terminals are Welded or secured directly to the ends, respectively, of

Patented Aug. 29, 196,7

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batteries of the assembly and obviating additional wiring and mounting lbrackets for the purpose of charging.

Another object is the provision of improved means for mounting the pillow bearings of an electric motor so as yto prevent rotation of the pillow bearings and also means for lubricating the pillow bearings.

Other objects and a fuller understanding of the invention may be had by refer-ring to the following description and claims, taken in conjunction with the accompanying drawings, in which: v

FIGURE l is a longitudinal sectional view in a horizontal plane of my improved driving unit with the upper shell portion removed to show the interior of the unit;

FIGURE 2 is a longitudinal sectional view of my driving unit taken in .a Vertical plane therethrough;

FIGURE 3 is a detailed sectional view taken through the line 3-3 of FIGURE 2;

FIGURE 4 is a cross-sectional view taken through the line 4-4 of FIGURE 2;

FIGURE 5 is a cross-sectional view taken through the line 5 5 of FIGURE 2;

FIGURE 6 is a plan View of one of the coupling elements used for coupling a knife lblade to a revolving round cam driven -by the electric motor of the unit;

FIGURE 7 is a side View of the coupling element looking in the direction of the arrows 7-7 of FIG- URE 6;

FIGURE 8 is a side view of the coupling element showing the shank of a knife yblade mounted in position therein and with the blade locked in the socket of the coupling element;

FIGURE 9 is a view similar to that of FIGURE 8 but showing the position of the parts with the blade unlocked in the socket of the coupling element;

FIGURE lO is an end view looking in the direction of the arrows 10-10 of FIGURE 2; and

FIGURE 11 is a cross-sectional view taken through the line 11-11 of FIGURE l0.

My driving unit has Ia housing composed of a lower shell 1I of suitable molded plastic material and an upper shell 12 of suitable molded plastic material which meets with the shell 11 to give a contoured smooth outer surface. Mounted in the housing near the rearward end thereof is a fbattery Vassembly 13. Forwardly of the battery assembly 13 in the housing is an electric motor denoted generally by the reference character 14, the motor being held in the housing by screws 16. The upper and lower shells are held together by the screw 15 interconnecting posts 11A of the lower shell and post 12A of `the upper shell.

Integral with and extending upwardly from the shell 11 just forwardly of the battery assembly 13 is a hollow bearing-supporting post 17. Integral and extending upwardly from the bottom wall of the she-ll 11 just forwardly of the motor 14 is another hollow bearing-supporting post 18. The posts 17 and 18 are in alignment with each other and are positioned so as to support respective pillow bearings 19 and 20 through which extend the rotating shaft of the motor 14. The posts 17 and 18 are round in cross-section and have a hollow interior opening at the tops thereof. Filling the lbore or interior of the post 17 is a lubricant-impregnated fibrous material 21. Similarly packed in the bore or interior of the post 18 is a lubricant-impregnated brous material 22.

The rearward pillow 'bearing 19 has a downwardly directed tongue or projection 19A of frusto-conical shape which substantially fills the upper end of the -bore or interior of the post 17 and which tongue 19A is in intimate engagement with the material 21 so as to receive lubricant therefrom Eby a capillary or wicking action. Similarly, the pillow bearing 20 has a downwardly directed tongue or projection 20A of frusto-conical shape which substantially closes the opening to the bore or interior of post 18. The tongue 20A is similarly in intimate engagement with the material 22 so as to receive lubricant therefrom by a capillary or wicking action. The pillow bearings 19 and 20, including their respective tongues 19A and 20A, are ,formed of a molded porous metal, such as bronze or the like, which permits lubricant to seep therethrough, that is, to be absorbed within the material of the pillow 'bearing and thus to provide lubrication for the rotating shaft within the bore of the bearing accommodating the shaft. Thus there is provided a good means for maintaining lubrication of the bearings and at the same time means is provided for preventing rotation of the bearings under the torque force imparted thereon by the rotation of the shaft. A cross-bar or strap 23 extends across the top of bearing 19 and is secured by means of screws 25 to the lower shell 11 and holds the bearing downwardly in position. In view of the means for preventing rotation of the bearing as described, it is not necessary to press down on the top of the bearing with the strap 23 as might otherwise be necessary. It is known that excessive force downwardly on such a bearing upon the supporting post of molded plastic material tends in time to distort and compress the material and thus to cause the bearing to get out of true alignment. However, with the arrangement shown and described, it is not necessary to impart such a strong downward force on the top of the bearing to resist to such rotation and thus to obviate distortion of the plastic supporting post. lf desired, additional means may be provided on the upper surface of the bearing 19 by making a small at or longitudinally-extending groove 19B thereon and by providing two small spaced slits 23A in the cross-bar 23 so that the material between the slits 23A snugly engage in the flat or groove. This aids in steadying and holding the upper portion of the bearing 19.

Similarly there is a cross-bar or strap 24 secured by screws 25 to the lower shell 11 extending over the pillow bearing 20 to hold the same in position. Similarly by reason of the anti-rotation means described, less force is required by the strap 24 to hold the bearing in position. Similarly, also, small slits 24A may be provided in the strap 24 to engage in a at or longitudinally-extending groove 20B in the upper surface of the bearing 20.

Carried by and extending forwardly of the rotating shaft of the motor 24 is a worm gear 26 which is enmeshed with a drive gear 27 located below the worm gear 26. Carried by the drive gear 27 are a pair of eccentrically mounted cams 28 and 29, these cams being positioned 180 degrees apart relative yto the axis of the drive` gear 27. The drive gear 27 with the cams 28 and 29 carried thereby is journaled on a shaft 30. This shaft 30 is carried on -two supporting posts 31 by two straps 32, the straps 32 being held drown on the posts by screws 25.

Connected .to each cam is a coupling or connecting element. A rst coupling element 34 is connected to cam 28 so as to be reciprocated as the cam 28 revolves. A second coupling element 35 is connected to the cam 29 so as to be reciprocated as the cam revolves.

Details of the construction of the coupling elements are better shown in FIGURES 6, 7, 8 and 9 wherein one of the coupling elements 35 is shown separated from the remainder of the driving unit. Coupling elements 34 and 35 are mirror images of each other and are similar in general construction except that they face each other in opposition and have their parts arranged as shown.

The coupling element 35 has a cam-engaging portion 35A which in turn has an elongated aperture 35B for accommodating the cam 29 whereby revolving of the cam 29 causes a reciprocating motion of the coupling element 35. A longitudinal portion 35C extends forwardly and has a recess or socket 35D formed therein, which socket has an open side facing inwardly, that is, toward the opposite coupling element 34 when in assembled arrangement. Near the forward upper end of the longitudinal portion 35C is an elongated slot 35E, the major dimension of which is vertical, that is, at right angles to the axis of the longitudinal portion 35C. This elongated slot 35E accommodates a first locking pin 36 which is moved upwardly and downwardly in the slot 35E.

The first locking pin 36 is carried by a pin-carrying member 38, preferably made of metal and having the shape illustrated in the drawings. The member 38 has a pivot-supporting portion 38A which extends into a small slot 35G provided in the upper portion of the element 35. Adjacent the readward end of the member 38 there is an angular ,abutting portion 38B extending at right angles to the major portion of the'member 38 and extending as a wing away from lthe coupling element 35. The arrangement of the pivot-supporting portion 38A in the small slot 35G is such that the member 38 on the pivot support swings between the positions illustrated in FIGURES 7 and 8 and the position illustrated in FIG- URE 9. The slot SSG permits any required play in the shifting of the axis of the pivot support 38A. The forward end of the member 38 has the locking pin 36 carried thereby which locking pin extends into the slot 35E. The swinging of the member 38 causes the pin 36 to move upwardly and downwardly in the slot 35E.

A wire spring member 40 has its forward end firmly i secured to the pin 36 on the side of the element 35 which is opposite the member 38. The rearward end of the wire spring 40 is bent to form 4an end portion 40A which end portion 40A is anchored in a hole provided in the element 35. Forwardly of the anchored rear end of the spring 40 there is a hooked boss 35E extending outwardly from the side of the element 35. The disposition of the hooked or overhanging boss 35E is such that the spring 40 may be moved upwardly and under' the boss 35E so that the boss 35F provides an abutment resisting further upward swinging of the spring 4.0. Thus, by the arrangement shown, the locking pin 36 is resiliently urged downwardly so as to be biased into the lower portion of the slot 35E. However, this resilient bias may be overcome by the pressing downwardly of the angular abutment portion 38B so as to pivotally swing the member 38 in.

in opposite directions a pair of adjacent knife blades 44 and 45. The blades 44 and 45 are mirror images of each other and are similar in construction except for having the parts arranged on opposite sides as illustrated. The knife blades have their forward portions broken away so that only the rearward portions thereof are shown in the drawings.

The blade 44 is shown mounted in the coupling element 35. The blade 44 has a tang portion 44A which is insertable in the socket 35D of the coupling element 35. Interconnecting the tank portion 44A and a cuttingV blade portion 44C is an offset portion 44B. The cutting blade portions of the two blades are disposed closely adjacent to each other so as to reciprocate in sliding engagement therewith. However, the tang portions of the two blades are spaced apart but parallel to each other and this requires the offset portions, such as the angular offsetk portion 44B. The inner upper edge of the tang portion 44A has a chamfered corner 44D which aids in introducing the tang portion 44A vinto the socket 35D. Also the charn fered edge portion 44D rst engages the locking pin 36 upon insertion of the tang portion into the socket so commodating the locking pin 36. When the pin 36 is in the notch 44E and held downwardly therein by the spring 40, then the tang portion 44A may not be withdrawn longitudinally from the socket 35D. However, upon pressing the angular abutment 38B downwardly, the spring 40 is overcome and the locking pin 36 is raised out of the notch 44E and clears the tang portion 44A and thus permits the blade 44 to be withdrawn from the driving unit.

Formed in the lower portion4 of the longitudinal portion 35C and protruding inwardly of the socket 35D, there is a small boss 35I which is in the path of the tang portion 44A when moved into the socket 35D. Formed in the wall of the longitudinal portion 35C and extending therethrough is a small slit 35H having the form illustrated. As .the plastic material of the element 35 is yieldably resilient, the movement of the tang portion 44A into the socket 35D depresses the small boss 351 which is accommodated by the small slit 35H. This provides a resiliently yieldable force tending to urge the tang portion 44A upwardly at that location and aids in providing a rm grasp upon the tang portion 44A.

The second blade-connecting element 35 similarly engages the blade 45. It also has a Wire spring 41 which urges a second locking pin 37 into position to interengage with a corresponding notch in the tang portion 45A of blade 45. The second locking pin 37 is similarly carried by a second pin-carrying member 39 which is actuated by an angular abutting portion 39A moved in a similar manner as the abutting portion 38A.

The two elements 34 and 35 are reciprocated longitudinally of the housing by the respective cams. The bottom of the shell 11 is provided with parallel guide slideways 11B along which the elements 34 and 35 slidably reciprocate. Positioned over the two reciprocal elements 34 and 35 isla'top slideway 43 which is mounted to the lower shell 11by screws 25. Thus, the elements 34 and 35 are held so that they may only reciprocate in parallel planes longitudinally of the housing.

The elements 34 and 35 are integral molded pieces of plastic material preferably reinforced with glass fibers for strength. Also preferably they are somewhat smooth and impregnated with a suitable lubricating material so as to provide good bearing characteristics where their surfaces engage the rotating cams and where their surfaces slidably engage the upper and lower slideways. Also the coupling elements 34 and 35 may be molded of nylon, Teiion or other such material having good bearing and sliding characteristics.

The blade 44 is provided with a guard 46 and the blade 45 is provided with a corresponding guard 47. The guards 46 and 47 are of asuitable hard plastic and aid in preventing food from moving' along the knife blade into the housing and also aid in handling the blades in assembling and disassembling them with the d-riving unit. The guards may be mounted on the blades by'providing two spaced holes through the blades 'where shown and by upsetting with heat and pressure the plastic material of the blade so as to provide a riveted or pinned over-portion holding the guard to the blade. For example, the guard 46 isy provided with riveted or pinned over-portions 46A l extending through the openings in the blade so as to r'mly hold the guard 46 to the blade.

' To release the blades 44 and 45 from the respective locking pins 36 and 37, a button 49 is provided which button protrudes outwardly from the housing near the forward upper end thereof. This release button 49 has two Iside arms 49A and 49B which are positioned over the'respective abutting portions 38A and 39A of the two pin-carrying members 38 and 39. Upon'th pressing downwardly of the button 49 both the abutment portions 38A and39A are depressed'and this in turn raises the two pins 36 and 37 simultaneously. Thelongitudinal extent ofthe bottom surfaces of the side arms 49A and 49B is such that the abutting portions 38A and 39A are always located under the side arms 49A and 49B and thus are in a position to be engaged thereby regardless of the relative positions of the elements 34 and 35 in their reciprocating motions. y

My arrangement also includes means for coupling the blade-release mechanism with the switch mechanism. Two switch leaves or reeds 51 and 52 are carried by a post 12B protruding downwardly from the upper shell 12. This post 12B has a lower hooked or angular portion 12C and the rearward end portions of the leaves or reeds 51 and 52 have openings therein through which protrude the hooked or angular portion 12C. A piece of electrical insulation 55 is positioned between the two leaves 51 and 52 at the location of the post 12B. The rearward ends of the leaves 51 and 52 are electrically connected in the usual way to wires 53 and 54, respectively, which wires in turn are in the electrical circuit vof the driving unit. The leaves 51 and 52 are of good electrical conducting material and also have spring-like characteristics so as to provide resiliently movable forward ends in the manne-r of leaf springs. The upper leaf or reed 51 has a downwardly directed contact 51A and the lower leaf or reed 52 has an upwardly directed contact 52A, the contacts 51A and 52A being in opposition so as to be in electrical engagement upon the leaves 51 and 52 being moved toward each other and thus to provide an electrical circuit through the contacts 51A and 52A.

Slidably mounted on the upper shell 12 is a slide switch button 50 which may be moved forwardly to on position and rearwardly to off position with the thumb or finger of the operator. The slide button 50 has guiding and securing portions 50A which t under the slideway along opposing shoulders formed in the shell 12. There is a boss 50B extending downwardly from the button 50 nearthe forward end thereof. This boss 50B is directed to slide along the upper surfaces of leaf 51 as the forward end portion of the leaf 51 is bent or tilted upwardly at an incline. Forward movement of the button g 50 to the position illustrated causes the boss 50B sliding forwardly to depress by a camming action the upper leaf 51. Rearward movement of the button 50 away from the forwa-rd end of the leaf 51 permits the leaf 51 to move upwardly by reason of its resilient action. Thus interengagement may be completed between the contacts 51A and 52A by the longitudinal sliding action of the button 50. The upturned forward portion of leaf 51 also by resilient action of the leaf causes a rearward camming action against boss 50B, resulting in button 50 being returned to off position when manually released from the forward position shown.

The lower leaf 52 also of a resilient or spring-like material extends forwardly under the button 49 and within the crotch formed by the branching of the portions 49A' and 49B. Downward pressing of the button 49 depresses the lower leaf 52 and thus moves the contact 52A downwardly away from a location where it could be contacted by the upper contact 51A. Thus with the lower leaf 52 depressed to its location shown in dotted lines in FIGURE 2, it is not possible for the sliding button 50 to causev interconnection of contacts 51A and 52A and thus to complete closing of the circuit. Thus, actuation of the lower leaf 52 by the button 49 is a safety switch which is auxiliary to or in addition to the manual sliding switch 50. Therefore, it is to be seen that the blades 44 and 45 may not be released by the locking pins 36 and 37 unless the button 49 is depressed, which simultaneously moves the switching elements to a position where an electrical circuit may not be completed andthe switch may not be closed. This provides a safety feature and thus prevents the blades from being removed while the motor is energized or while the motor ycould be energized by reason of the slide button 50 being left in a forward position. The button 49 is resiliently urged upwardly by the being turned on inadvertently by forward positioning of the sliding button 50.

My invention also includes a novel method of mounting the contacts to the batteries of the assembly y13. The batteries of the assembly 13 are of the rechargeable type whereby upon the unit being placed in a charging unit with the batteries being properly electrically connected with the charging unit, the batteries may be periodically recharged as required. In the illustration, the assembly 13 consists of batteries 57, 58, 59 and 60 held together by a band 61. The batteries are interconnected in series and the batteries in turn are electrically connected to the motor Y14. Instead of having separate spring contactI elements carried by the housing, I mount a iirst spring contact arm 62 to battery 57 at the base thereof and a second spring contact arm 63 to the battery 59 at the post thereof. The contact arms 62 and 63 are of resilient leaf spring material and are also electrically conductive. One end of each contact arm 62 and 63 is welded or otherwise mechanically and electrically bonded to the metal end of the battery upon which it is mounted, arm 62 being mounted to battery 57 and arm 63 being mounted to battery 59.

The lower shell 11 has an end wall 11C projecting upwardly at the end to close the end of the housing. EX- tending through this end wall 11C are two spaced openings 56A and 56B, which expose the arms 62 and 63 to contacts protruding upwardly from a charging unit (not shown). The lowermost ends of the arms 62 and 63 are accommodated in recesses 56C and 56D, respectively, so that the arms 62 and 63 are confined within the housing and may not move outwardly therefrom. As seen in the drawing, each arm 62 and 63 is engageable by a protruding contact or stud element of an electrical charging unit. By the arrangement shown, it is not necessary to have brackets and other such devices mounted to the housing for carrying the contact arms and it is also not necessary to have the contact arms interconnected with wiring and the like to the batteries. The arrangement provides a good mechanical mounting with a minimum of parts for the contact `arms and also assures a good electrical interengagement for electrically connecting the batteries with a charging unit.

A unique and highly useful driving unit is provided by the above described and illustrated structure. Also the several structural features above shown and described in themselves have a marked utility and provide improved results over comparable structures.

The present disclosure includes that contained in the appended claims, -as well as that of the foregoing description.

Although this invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred iform has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as hereinafter claimed.

What is claimed is:

1. An electric driving unit having an electric motor for reciprocation of a knife blade or the like, the combination of locking means reciprocal with the knife blade and carried by the unit for locking a said knife blade against Withdrawal from the unit, manually operable release means carried by the unit for moving the locking means to permit withdrawal of the knife Iblade from the unit, switch means manually operable for connecting and `disconnecting the electrical .circuit of the unit for energizing and de-energizing the said electric motor, said switch means having a first electrical Vcontact member and a second electrical contact member movable relative to each other for connecting and disconnecting said circuit, said manually operable release means being positioned to engage one of said contact members and upon movement of the release means to position for releasing the locking means, concurrently to move said one contact member to an inoperable position where it cannot be contacted by the other of said contact members, whereby operation of the release means modifies the switch means to prevent energization of the said motor.

2. An electric driving unit as claimed in claim 1 and in which said one Ycontact members is resiliently biased into engagement with said release means to urge the release means into non-releasing position.

3. An electric driving unit as claimed in claim 1 and in which said releasing means is positioned to simultaneously release a plurality of locking means Yeach associated with a separate knife blade of a plurality of knife blades operated by the driving unit and in all reciprocal positions of each of the locking means.

4. An electrical driving unit for counter-recpirocating a pair of knife blades or the like, comprising a longitudinal housing, a pair of blade-coupling elements mounted in said housing for longitudin-al reciprocations therein in opposite directions, an electric motor in said housing, eccentric means driven by said motor tand operatively connected to said elements for reciprocating the same in opposite directions, a locking pin carried by each said element and reciprocal therewith, each said locking pin being adapted to cooperate with a said blade for releasablylocking the blade to a said element, a release member carried by the housing and positioned to move both of said locking pins out of locking position upon actuation of the release member, a switch mechanism for controlling the energization of said motor by manual m-anipulation of the switch mechanism to on and olf positions, said switch mechanism comprising at least two parts one of which in one location is positioned in cooperative relationship with the other part for permitting the closing of the motor circuit upon movement ofthe ii-rst pant to on position and in a second location is positioned out of cooperative relationship with said other Apart for preventing closing of the motor circuit notwithstanding any movement of the irst part to on position, and means interconnecting said release member and said switch mechanism to move said one part of the switch mechanism to said second location to thereby place said switch mechanism in an inoperative condition preventing energization of said motor upon operation of the release member to the posi` tion for releasing said locking pins.

5. An electrical ldriving unit as claimed in claim 4 and including resiliently yieldable means .urging said locking pins ,into position Ito lock Ithe bladesto the `respective `bladecoupling elements, and spring means for resiliently urging said release member into inoperative position. Y

6. In yan electrically driven power unit having a reciprocal tool releasably connected thereto, the `combination of reciprocal means reciprocated by the unit, locking means for releasably lock-ing the tool ,to the reciprocal means, releasing means for ,moving the locking means to unlocking position, switch means having a rst part movable toward and away from a second part thereof between energizing position land de-energizing position .for controlling the electrical energization and de-.energization ofthe unit, said second Ypart of the switch means being movable ltoward the first ,part to a rst location for cooperating .with the .first part to `permit ,the .closing of the switch means andthe electrical .energization of the unit, Iand being movable away from said first part `to a second location out of cooperative relationship with the first part to prevent the closing of the switch means and the electrical energizationof the unit, and interconnecting means interconnecting thereleasing means and said second part of the switch means to move the same to said second location to thereby cause inoperativeness of the switch means preventing electrical energization of the unit upon operation of the releasing means to move the locking means to unlocking position.

be interengaged by said other part upon actuation of the switch mechanism toward energizing position, said springbiased part being disposed to engage and resiliently oppose movement of the releasing means to unlocking position.

9. In combination, a coupling member adapted -to be reciprocated by the mechanism of an eletrically powered unit and to -be coupled to a blade or the like upon insertion of an end portion of the blade in the member for corresponding reciprocation of the blade, said member being of integral molded plastic material having an elliptical aperture for Ireceiving a revolvable cam to reciprocate the member upon revolution of the cam, said member having a slot formed therein, a locking pin carried by the member in said slot and projecting into the path of the blade in the member to cooperate with a notch in said blade end portion for locking the blade in the member, and a resiliently biased supporting member pivotally carried by the coupling member to reciprocate therewith for holding said locking pin and lurging it in a direction in said slot toward a bl-ade in said member to engage in said notch, said slot being disposed to permit said locking pin to move in an opposite direction Vagainst the bias of said supporting member away from a said blade in the coupling member and out of a said notch in the blade end portion thereof, said supporting member having an engaging portion extending therefrom for the pivotal swinging of the supporting member upon actuation of said engaging portion toward a blade end portion in said coupling member and the corresponding movement of the locking pin away from a said blade end portion.

10. The combination as claimed in claim 9 and including a releasing member disposed for engagement with 4a said engaging portion of the supporting member to actuate the same in any of the varying positions of the engaging portion during its reciprocal movement with the coupling member, and arranged for concurrent engagement with a like engaging portion of the supporting member on a similar coupling member reciprocable along a parallel path in an opposite direction in any of the varying positions of the like engaging portion.

11. In an electric knife having reciprocal coupling elements counter-reciprocated by an electric motor, the said coupling elements and motor being mounted in a housing,

the coupling elements being adapted to be coupled to and to counter-reciprocate adjacent knife blades, each blade having lock-engaging means carried by the tang portion thereof insertable into the said housing, the combination of locking means carried by each said coupling element adapted to interlock with said lock-engaging means of a said blade tang portion, releasing means for concurrently releasing both said locking means from said lock-engag- 4 ing means, m-anual electric switch means for controlling the energization of said motor, said switch means including two cooperable contact members, the first contact member being movable toward and .away from the second contact member for opening and closing the motor circuit through the switch means, the second conta-ct member being movable between a first location for cooperation with the rst contact member to permit closing of said motor circuit and -to a second location out of cooperative relationship with the lirst contact member to prevent closing of said motor circuit notwithstanding any movement of the irst contact member toward said second contact member, and means interconnecting said releasing means land said second contact member of the switch means to move said second contact member to said second location and thereby to render said switch means to a non-operative condition preventing energization of said motor upon operation of the releasing means to a position for releasing said locking means.

12. The combination claimed in claim 11 and in which said switch means includes two resilient contact arms movable relative to each other for completing and breaking the electrical circuit to the motor, one of said resilient contact arms being engageable by said releasing means to be moved out of reach of the other resilient contact arm to prevent completion of said circuit upon movement of the releasing means toward said position for releasing the locking means, said one resilient arm in engagement with said releasing means also resiliently biasing said releasing means away from said releasing position.

References Cited UNITED STATES PATENTS 1,390,702 9/ 1921 Hammond 30-272 X 2,627,882 2/ 1953 Kleinsmth.

2,706,544 4/ 1955 Schuman.

2,807,732 9/ 1957 Kurtovich.

3,234,649 2/ 1966 Preble et al. 30-272 3,276,118 10/ 1966 Taylor 30-272 JAMES L. JONES, JR., Primary Examiner.

Claims

1. AN ELECTRIC DRIVING UNIT HAVING AN ELECTRIC MOTOR FOR RECIPROCATION OF A KNIFE BLADE OR THE LIKE, THE COMBINATION OF LOCKING MEANS RECIPROCAL WITH THE KNIFE BLADE AND CARRIED BY THE UNIT FOR LOCKING A SAID KNIFE BLADE AGAINST WITHDRAWAL FROM THE UNIT, MANUALLY OPERABLE RELEASE MEANS CARRIED BY THE UNIT FOR MOVING THE LOCKING MEANS TO PERMIT WITHDRAWAL OF THE KNIFE BLADE FROM THE UNIT, SWITCH MEANS MANUALLY OPERABLE FOR CONNECTING AND DISCONNECTING THE ELECTRICAL CIRCUIT OF THE UNIT FOR ENERGIZING AND DE-ENERGIZING THE SAID ELECTRIC MOTOR, SAID SWITCH MEANS HAVING A FIRST ELECTRICAL CONTACT MEMBER AND A SECOND ELECTRICAL CONTACT MEMBER MOVABLE RELATIVE TO EACH OTHER FOR CONNECTING AND DISCONNECTING SAID CIRCUIT, SAID MANUALLY OPERABLE RELEASE MEANS BEING POSITIONED TO ENGAGE ONE OF SAID CONTACT MEMBERS AND UPON MOVEMENT OF THE RELEASE MEANS TO POSITION FOR RELEASING THE LOCKING MEANS, CONCURRENTLY TO MOVE SAID ONE CONTACT MEMBER TO AN INOPERABLE POSITION WHERE IT CANNOT BE CONTACTED BY THE OTHER OF SAID CONTACT MEMBERS, WHEREBY OPERATION OF THE RELEASE MEANS MODIFIES THE SWITCH MEANS TO PREVENT ENERGIZATION OF THE SAID MOTOR.