US3151515A

US3151515A - Paper trimmers

Info

Publication number: US3151515A
Authority: US
Publication date: 1964-10-06
Anticipated expiration: 1981-10-06

Description

Oct. 6, 1964 L. SUVERKROP 3,151,515

PAPER TRIMMERS Filed Jan. 15 1959 I5 Sheets-Sheet 1 LMSW A TTO/P/VE Y Oct. 6, 1964 SUVERKROP 3,151,515

PAPER TRIMMERS Filed Jan. 15, 1959 3 Sheets-Sheet 2 HVVENTUR.

A Traz/YE 7 L. SUVERKROP PAPER TRIMMERS Oct. 6, 1964 3 Sheets-Sheet 3 Filed Jan. 15, 1959 v United States Patent 3,151,515 PAPER Tenn/runs Lew Suverkrop, R0. Box 436, Bakersfield, Calif. Filed Jan. 15, 1959, Ser. No. 786,943 13 Claims. (Cl. 83-330) This specification describes improvements applicable to paper trimmers generally, and particularly to those used for trimming photographs, blueprints, photostats, and the like. More specifically they apply to the type of print trimmer in which the work board, upon Whose surface the print is held during the trimming operation, is hinged on the base of the trimmer. in this type the work board generally slopes down toward the operator as he stands before the trimmer. The hinges are at the lower, forward edge of the work board, while the opposite edge of the board is fitted with the upper of two shearing blades. This upper blade is secured at its ends to the work board with its cutting edge parallel to the higher, rearward edge of the board, and slightly over and beyond that edge. Also hinged to the base of the trimmer is the lower shearing blade, along a hinge line that is substantially below and nearly parallel to the upper blade. The cutting edge of the lower blade engages with the cutting edge of the first blade, at one end thereof when the work board is in the up position. From the point of engagement, this cutting edge slopes downward toward its other end in such manner that shearing contact between these two blades progresses from one side to the other of the trimmer, along the blades, as the board is pressed downward by the operator. A spring keeps the lower blade in proper contact with the upper one during the shearing process. A second spring returns the work board to its terminal up position after the operator has withdrawn his pressure from it; and a stop limits this upward motion of the board to a position where the two shear blades are apart and ready to start shearing a print placed between them. Clearly, the print may be manipulated and held throughout the trimming process since the cutting action is effected merely by pressing downward on the work board without removing the hands from the print.

The type of print trimmer just described has been known for years. At first glance, it seems to have obvious advantage over the common, so-called photographic type of trimmer. In this latter type the work board forms the base of the trimmer. It is fitted with a shearblade that forms the sharp upper edge along the right side of the board as the operator views it. A second blade is pivoted at one end to the far end of the first blade. Holding the print with his left hand, he grasps the free, handled end of the second blade with his right hand, and brings it down so as to trim the print placed between the blades, cutting it along the shearing edge of the board.

Over this, the advantage that immediately appears in the hinged work board type trimmer, previously described, is that of speed. This is especially apparent when the upper surface of the work board is finished to have a low coeficient of friction, thereby ofiering little resistance to movement of the print while manipulating it into position for cutting. in such cases operators quickly learn to coordinate movements of positioning the print and pressing the work board to effect shearing. This makes possible a work speed with the hinged board trimmer that is several timesthe maximum possible with the other type. However, hinged work board trimmers heretofore have also been characterized by offsetting disadvantages; and these have prevented this type from becoming so popular as it should become once the problems of these disadvantages are solved.

The new constructions in hinged board trimmers disclosed in this present specification followed engineering l atented Get. 6, 1984 analysis of trimmers to determine their inadequacy or effectiveness in meeting desired objectives noted in details of their functioning. Briefly, arnong the particular o'ojectives of the present invention are the following: (1) To secure automatically the print during trimming with a device which also makes a convenient guide and gage against which a border or other line on the print may be aligned so that the trim line will be parallel to and at a desired distance from such a line. Thus securing the print will hold it against the lateral forces, always present in shearing action, which frequently result in a curved instead of a straight trim line. This objective further is to make it feasible to finish the work board with the lowest possible coeflicient of friction so as to facilitate rapid manipulation of the print into alignment for trimming. (2) To provide a construction which makes it possible to introduce motion in the shear blades sufficiently in advance of the instant at which actual paper cutting starts so that, as a result of kinetic energy thicker paper may be out than has been possible heretofore. (3) To provide a simple means by which action of the work board return spring may be adjusted to achieve maximum speed and minimum operator fatigue. (4) To provide an upper (moving) blade construction which will combine lightness, minimum thickness, and adequate stillness, mainly to reduce materially the inertia of the moving work board and thereby to increase trimming speed while decreasing operator fatigue. (5) To provide a device for applying spring action to the lower blade in such manner that, during use, there will be eliminated the blade flutter present which is subjectively annoying and which objectively interferes with proper functioning. (6) To provide a simple stop or gage pin which may be readily retracted from or brought into use at a frequently used trimming dimension, thereby increasing the speed of accurate trimming. (7) To provide details of construction in the complete trimmer which, combined with their arrangement, make it easy (a) to fold the trimmer into minimum space for shipment or storage, without disturbing any adjustment of the trimmer; and (b) to open and assemble the trimmer into position ready for useall quickly and without tools of any kind. These and other objectives of the invention and their applications to other trimmers and various other devices will be clear from the following description and the attached drawings, in which FIG. 1 is a perspective view of such a trimmer, ready for use, taken from a point quartering on the front of same;

FIG. 2 is another perspective view of such a trimmer, ready for use, taken from a point quartering on the rear of same;

FIG. 3 is another perspective view, taken from a point quartering on the frontof same, with the work board raised from the operating positionso as to disclose parts concealed in FIGS. 1 and 2, and to indicate how parts of the trimmer are folded for shipment or storage;

FIG. 4 is a diagram, in the form of a view from one end of the trimmer, showing the manner in which it may be folded;

FIG. 5 is a cross section along the line DD in FIG. 6;

FlG. 6 is a view in the direction of the length of the lower blade, showing construction of the device for applying spring pressure to the lower blade, and the stop for limiting upward motion of the work board;

FiG. 7 is another viewof the spring pressure device shown in FIG. 6; 7

FIG. 8 comprises two views of the bearing in which the spring pressure. device of FIG. 6 oscillates and by means of which it is secured to the base of the trimmer;

FIG. 9 shows assembly of parts by means of which adjustable spring pressure is applied to the work board to raise it after trimming;

FIG. is a cross section along line C-C of FIG. 9 showing construction by means of which spring tension adjustment is made and held;

FIG. is a plan view from below showing the print grip actuator of FIG. 13;

FIG. 16 is a View of the support shown in FIG. 11, taken from the rear of the work board;

FIG. 17 is a view from the end of the work board showing the support seen in FIG. 11;

FIG. 18 comprises two views of the print grip actuator adjusting lever seen in FIGS. 13, 14, and 15; FIG. '19 comprises two views of the print grip actuator adjusting lever seen in FIGS. 13, 14, and 15;

FIG. is a view of parts seen in FIG. 14, taken from the rear of the work board;

FIG. 21 is a cross section taken along lines AA in FIG. 12, to show better the form of the print grip blade and the auxiliary support;

FIG. 22 is a plan view of the adjustable gage pin device;

FIG. 23 is a side elevation of the gage pin device shown in FIG. 22; and

FIG. 24 is a cross section along the lines BB of FIG. 22.

Referring to FIGS. 1, 2, and 3, work board 1 is attached by hinges 2 on support strip 3 which is integral with base 4. Brackets 5, fixed to the rearward corners of board 1, serve for securing the upper shear blade 6 at its ends by means of screws 7. Lower shear blade 8 is attached by hinge 9 to strip 10 integral with base 4. Stop 11 is secured to blade 8 by means of screws 12 through elongated holes in stop 11 so that the upper stoppng position of board 1 may be adjusted. Downward motion of board 1 is limited by rubber bumpers 13 on support blocks 14 integral with base 4. V

To eliminate shock when'board 1 is brought to rest at its upper terminal position, metallic bumper 15, detailed in FIGS. 5 and 6, is provided with rubber washer 16. Bumper 1'5is free to slide in the hole provided in stop 11 where it is retained by a cotter pin or other ordinary means. 7

Lower blade spring device.'-Heretofore in trimmers of this type, the lower blade [corresponding to numeral 8 in the accompanying drawings] was forced into required shearing contact with the upper blade 6 by means of a tension spring. One end of this spring was anchored to the base 4 of those trimmers; and the other was attached direct to the lower blade 8. So that the descending board 1 would clear it, was necessary to attach-theother end of this springto the lower blade 8 ma point which gave only'a short lever arm, measured radially from the hinge axis. Aside from that kind of spring arrangement being unsightly due to its makeshift and Rube Goldberg appearance, it invariably resulted in excessive flutter of the lower blade 8' every time the board 1 was depressed This incidental flutter was not merely subjectively annoying; It is of a kind that caused undue wear in thecutting' edges of

both'shearing blades

6 and 8 of'those trimmers;

In'the trimmer covered by this specification, that objectionable condition is corrected by a novel means of applying spring pressure to lower blade 8. The spring pressure is not direct. It is applied through a spring loaded lever 17. Bythismeans the pressure on blade-bis applied at a point well removed from the hinge axis and all harmful flutter is eliminated. Spring lever 17 is of round bar stock bent into the form shown in FIGS. 6 and 7. The upper end is fitted with roller 18, preferably of graphite impregnated nylon or like material. This roller is in rolling contact with the outward, rearward surface of stop 11. The lower end of lever 17 is rotatably secured to base 4 by means of bearing=19 detailed in FIG. 8. Torsion spring 20 has one end bearing against base 4 and the other end formed so that it presses against lever 17. Lever 17 is as long as possible but still of such length that roller 18 continues to bear against stop 11 when blade 8 is laid'fiat on base 4 as seen in FIG. 3.

Adjustable work board spring.--Heretofore, in trimmers of this type, the springs employed for returning the work board to its upper terminal position varied from studies have indicated that. not every one of these is of minor importance; and, while one or more of them individually may be of minor importance, in combination they very materially do affect the speed and convenience with which trimmers of this type can be operated.

As shown in FIGS. 3 and 9, work board return spring 21, one end of which reacts against pin 22 in shaft 23, is formed at its other end so as to act against the under side of lever 24 which is free to rotate on shaft 23. .The free end of lever 24 has an integral pin upon which roller 241 is rotatably secured. Roller 24-1, through a suitable pressure plate, applies the pressure to board 1. One end of shaft 23 is carried rotatably by support 25 secured to base 4. The other end of shaft 23, of larger diameter, is either hobbed or knurled with teeth to engage with the thread of adjusting screw 26. Sui-table holes in pillow block' 27 receive the adjusting screw 26 and the worm gear formed on shaft 23, rotatably and with teeth and thread in proper mesh. In other applications where adjustment must be made while the parts are under heavy load, it may be desirable to provide a steel ball to take the thrust of adjusting screw 26 and make it easier to turn, particularly if pillow block 27 is made of soft material such as that in many die castings. However this is hardly necessary inthe present trimmer. It has been found that when board 1 is raised to the position shown in FIG. 3 for adjusting the action of spring 21, thatrposition is so far above the place where spring 21 is under load, adjustment screw 26 can readily be turned by hand. This can be done even when it is an ordinary headless set screw protruding but slightly above the upper surface of pillow block 27. But it has been found that a minute adjustment of screw 26 very materially affects the efl'lciency of the trimmer. For this reason it is preferable that the upper end of adjustment screw 26 have a disk-like form with numbered graduations which can be noted against an index 28 fixed to pillow block 27 as seen in FIGSJIO and IO-A. This means is convenient to the operator and greatly speeds'up the certainty of precise adjustment and readjustment of spring 21 so that it gives exactly the kind of motion in board 1, both upward and downward, which will achieve maximum speedand minimum operator fatigue. Holes in pillow block 27 provide for firmly secur-' ing it to base 4 by means of screws.

Print guide andgrip.Located toward the operator 7 from and parallel with blade 6 isprint grip 22 shownin details of'FIGS. 11, 12,13, 16, 17, 20, and 21. .This is preferably of heavy transparent plastic sheet, marked on its underside with guide lines 30 running parallel with its length. Grip -29 is attached, by means of binder head screwsfil through'countersunkholes in it, to grip bar 32. Grip bar 32 is preferably of square cross-section this dimension equivalent to a common increment of distance such as A inch at which increment it may be convenient to space guide lines 30. Moreover, it is preferable to locate the edges of grip 29 and of grip bar 32 so that each is at a convenient multiple of that increment from the cutting edge of blade 6. These features make it easy to position quickly a print so that it will be trimmed parallel to and at a desired distance from a border or other line of the print. The edge of grip 29 nearest the operator may be turned upward as indicated in the cross section of FIG. 21 so as to funnel prints under grip 29. This construction strengthens grip 29 and makes it possible to locate grip 29 close to board 1 without in the slightest hindering the quick placement of a print for trimming. It will be noted from the cross section in FIG. 21 that the lower side of blade 6 may be relieved, giving another funnel form further to assist in the rapid placement of prints.

At its ends, grip bar 32 is round in cross section to serve as journals where it is rotatably held by grip bar supports 33 each of which is provided with a boss 34. The holes of support 33 are located at the apices of a triangle, one side of which is substantially parallel to the surface of board 1. This side extends from the pivot screw 35 to the axis of grip bar 32. A second side, perpendicular to board 1, extends from pivot screw 35 to holding screw 36. The hole for pivot screw 35 provides bare clearance, while a considerably larger hole in support 33 surrounds holding screw 36. This provides for considerable angular movement of support 33 about pivot screw 35, resulting in movement of grip bar 32 up and down with respect to board 1. The adjustment is made with both

screws

35 and 36 somewhat loose. Having made the adjustment, each

screw

35 and 36 is tightened against its washer 37 so as to secure support 33 to its adjacent bracket 5.

By action which will be explained below, immediately the operator presses boardl to shear the print, and prior to the beginning of shearing action, print grip 29 rotates about the axis of grip bar 32 so that one edge of grip 29 presses on the print and secures it to board 1. This holds the print firm against the lateral forces of shearing, while shearing proceeds. Since the print cannot move with respect to the edge of upper blade 6 during this action, the trim line will duplicate the straight form of that blade. To assist in the effectiveness with which grip 29 secures the print, it is preferable that the part of board 1 that is immediately below the gripping edge of grip 29 be surfaced with friction material 38 such as sponge rubber or abrasive sheet, as indicated in FIG. 21. It is preferable that the remainder of the surface of board 1 be covered with material that lends itself to developing a very low coefficient of friction. Obviously, this greatly facilitates quick manipulation of the print into proper alignment. For this part 39 I have used linoleum, suitably waxed. The color of the linoleum, such as green or black, may be chosen to minimize glare.

Print grip rzctzmton-Thc rounded section at one end of grip bar 32 is extended to carry grip actuator roller lever 40 by set screw 42. As indicated by the drawings and made clear by details of FIGS. 18 and 19, boss 43 on actuator lever 49 extends into hole 44 in adjustment lever 41. Hole 44 in lever 41 is sufficiently larger than boss 43 to allow considerable angular movement of lever 40 with respect to lever 41 when they are mounted on their journal of grip bar 32. This provides for convenient adjustment of gripping action. To facilitate making this adjustment and to secure levers 4t) and 41 to one another after the adjustment has been made, adjusting screws 45 in adjustment lever 41 have their pointed ends resting in a suitable groove 46 in boss 43.

Crank pin 47 on lever 40 carries roller 48 together with a cotter pin and washer or other means for keeping it there. A second roller 49, aligned with roller 48, is similarly located and secured on roller shaft 50 which is integral with roller shaft support 50-1. This support 501 is fastened to the underside of bracket 5. Crank pin 47 and roller shaft 50 are drawn toward one another by spring 51. Looped ends of spring 51 fit into suitable grooves in pin 47 and shaft 50. Preferably,

rollers

48 and 49 are grooved to accommodate grip actuator cam sector 52 between them as indicated in the drawings. Sector 52 is so located on base 4 that its larger curves center on the axis of hinges 2. These facts combine to make sector 52 remain stationary when the trimmer is operated, although only pivotally held on base 4. The lower end of sector 52 is positioned and rotatably secured by shoulder screw 53 to bracket 54 which is fixed to base 4. It is preferable that ordinary means in these parts allow making some vertical adjustment of shoulder screw 53 and some lateral adjustment of bracket 54. Sector 52 is of constant thickness. But its upper part is of width which permits spring 51 to draw lever 40 into a position that makes grip 29 parallel to and clear of board 1 as indicated in FIG. 21. Below this upper part, sector 52 is wider. its width is such that when

rollers

48 and 49 span it, due to the camming action where the narrow and wide parts of sector 52 meet, actuator lever 40 has rotated grip bar 32 enough to cause the edge of grip 29 nearest blade 6 to bear on a print beneath grip 29. As shown by the drawings, the rearward edge of sector 52 is a single, continuous curve that rests against roller 49 Whose axis is stationary with respect to board 1. The opposite, forward edge of sector 52 is formed by two curves having a comon center which is also the center of the curve on the rearward edge. Thus the upper part of sector 52 is of contant radial width and narrower than the lower part, also of constant width. The cam in sector 52 is formed where the narrow and the wide parts joint. This is preferably in the form of a fourth radius, equal to that of the groove in roller 48 where it bears against sector 52. With this construction, movement of lever 40 and therefore grip 29 begins at the very instant that the operator starts the downward motion of board 1; and very little motion of board 1 is required for the cam of sector 52 to complete the movement of actuator lever 40 and the consequent action of grip 29 in securing the print on board 1. This makes it possible for the trimmer to secure a print throughout the shearing action, automatically; and also to leave the print entirely free for alignment manipulation before shearing begins.

Due to the slender proportions of grip bar 32, reactions from its rotation to elfect gripping the print cause it to bow upward. To insure constant gripping action of grip 29 throughout its length, one or more auxiliary grip bar supports 55 may be provided. Support 55 is adjustably secured to blade 6; and its underside rests against a cylindrical surface provided on grip bar 32 as indicated in FIG. 21.

Kinetic initial shearing.-Heretofore in trimmers of this type, the

shear blades

6 and 8 remained in shearing contact when the board 1 was in its terminal up position. In them, the point of shearing contact between the blades and the point in the paper where shearing would begin were co-incident. Consequently, shearing began with zero velocity in the upper blade 6. Considerable static pressure frequently was required. of the operator in order to start the cut although, if he could get it started, he might experience no great ditiiculty in continuing it. By the nature of such trimmers heretofore, in the absence of levers or other means of mechanical advantage, they were considerably limited in paper thickness the could cut, compared with the photographic type of trimmer with its lever action.

In the present trimmer, blade guide 56 (see FIGS. 2, 3, l6 and 17) makes it possible to raise blade 6 a useful distance above and out of contact with blade 8. In the absence of this guide 56, when board 1 goes to its terminal up position, blade 8 would drop against v'erti'cal plane through its middle.

blade of similar rigidity. Y Retractable gage pin.' -Trimmers of this type are used r 7. board 1 in a place below blade 6. When next board 1 was depressed, blade 8 Would'hang up on board 1, or

blades

6 and 8 would collide, In either case, shearing could not take place. With guide 56 properly adjusted, when board 1 moves to its terminal up position, blade 8 bears against the upturned outboard face of guide 56 in such position that the next downward movement of board 1 brings

blades

6 and 8 into proper shearing engagement with one another. In the interval of time between the start of the downward motion and the start of actual shearing, kinetic energy is developed. This is sufiicient to permit shearing thicker paper, without additional effort on the part of the operator. This has been found to be true, even when the time interval is so small as not to be noticeable to the operator. In addition to increasing the thickness that may conveniently 'be cut with this trimmer, the time interval made possible by blade guide 56 further insures that the gripping action (caused by the cam on sector 52) will be completed before shearing begins.

Low inertia shear blade.--Operating speed of this type of trimmer is very much affected by total weight of parts secured to board 1, and by the distance to the center of mass of this aggregate measured from the hinge axis. Even when properly counterbalanced by return spring 21, any increase in weight means an increase in inertia. This means a reduction in the speed with which it may be moved, for a given effort on the part of the operator. In this, the most important factor is upper shear blade 6. Of necessity it is located on board 1 as far as possible from the hinge axis, whereas the placewhere the operatorshands press upon board 1 is much closer to that axis. He is at a disadvantage in causing downward move- 'ment of blade 6, and reduction in its weight is much to be desired. But a number of factors make the problem difficult. To reduce weight, the blade cannot indiscriminately be reduced in area, or made of material chosen only for low specific gravity. Blade 6 is a cutting tool and this requirescharacteristics of tool steel rather than those found in a light aluminum or magnesium alloy. It

must be sufliciently rigid to resist lateral forces from lower blade 8, particularly those which may result in a curved trim line. Light and rigid structural sections cannot be chosen if their crosswise dimension unduly covers a print to interfere with guiding it into place for trimming. In addition to resisting direct forces incidental to its function, the form must otherwise be stable.

Blade 6, detailed in cross section in FIG. 21', is composed of three parts, permanently joined together by thermosetting plastic cement or by other means. It makes use of a light metal such as aluminum, yet has the cutting quality of tool steel; and its design takes into account the fact that light metals have a coeflicient of thermal expansion of about twice that of steel. Since .only the cutting edge need resist abrasion and wear, the

tool steel part of the blade is confined to the outer part 564. The unit of greatest area is the central part 57.

Largely by itself but also in combination with the other 58 is of steel; this need not. behard, but should have the same cross section and the same coefiicient of expansion 'as outer part 56. 'In central part 57 it ispreferable that the same crosssectional area appear on'each side of a In this construction bending forces resulting from dilferential thermal expansion on oneside of the neutral axis are counterbalanced by like forcesonthe other side. 'Thej'result isa blade of suitable rigidity that is thermally stable as to straightness, with. a weight of about one-half-that of an all-steel for cutting prints to many different dimensions. For this 8 purpose a combined scale'and squaring guide 59 is adjust ably secured to board 1. A large part of the trimming work is confined to a few common dimensions such as 8 /2 inches and 11 inches. It has beencommon to mark prominently such dimensions on trim guide 59 so as to call the operators attention to them.

The present trimmer is provided at each such dimension with a positive stop in the form of a gage pin'69 shown in FIGS. 22, 23, and 24. An important feature of this gage pin 60 is it retractable nature. Quickly'and easily, with but a slight motion of the operators hand above or below board 1, it is placed out of or brought into use. Gage pin 6%) slides freely in the hole provided for it in gage pin body 61, but is kept at whatever position is given it, by retaining hall 62 acting against the wall of that hole due to retaining ball spring 63. The mouth of the hole in pin 69 which carries ball 62 and spring 63 is slightly deformed so as to retain ball 62 against loss when pin 60 is out of body 61. Body 61 is shouldered to assist in retaining it properly in board 1 with its upper surface flush with board 1. A saw out forms an integral spring 64 from the body 61. This isgiven a form'to increase the carries pin 69 is eccentric from body 61.

friction between body 61 and its hole in board 1 so as to prevent accidental movement. The hole in body 61 which This provides for minute adjustment of the actual distance from the gaging side of gage pin 57 to the cutting edge of the trimmer. To effect this adjustment, the top of body 61 is slotted so that body 61 may be turned conveniently with a screwdriver. v I i When using two gage pins 60 in trimming the two dimensions of a nurnber of prints, the pin 60 at the longer dimension may remain protruding as this in no Way interferes with use of the other pin 60 at the shorter dimen sion. Only the pin 60 at the shorter dimension need be manipulated, and this need not be moved in or out except to change it when going from one to the other of the dimensions. i

Design for foldability-Blocks14 as shown in FIG. 3

are so located on base 4 as to permit blade 8 to clear them when it is folded against base 4. It is a simple matter to disengage stop 11 from board .1; blade 8 is position. from board 1 and drop to the position it has in'FIG. 3 where it is clear of any interference with board 1 in any position. Board 1 may now be pressed down into a space of minimum height indicated by the diagram in FIG. 4. Only a few seconds are required for the entiredisassembly.

'Re-assembly is similarly .a speedly job. After raising board 1 to above the normal terminal position for. it, blade 8 is turned rearwardand held there while sector 52 is lifted to a; position where its 'free end will enter between

rollers

48 and 49, whereupon board 1 is lowered and blade 8 is released so as to contact blade 6 with bumper 15 above blade 6. Then board l may be released to the action of spring 21 and the trimmer will be ready for work. a

The construction makes it possible to ship'the trimmer fullyadjusted, in a package of minimum size, andwithout presenting the customer with any assembly problem worth mentioning. If the trimmer is shipped with board return spring 21 adjusted, the shipping case will hold board 7 Weight into the form indicated in the diagram of FIG. 4.

' To do this it is a. simple matter to relax spring 2 1"by' turning adjustment screw 26 after noting on its scale the proper.v position for tension against board 1." This speeds the re-establishment of proper adjustment of screw'2 6 when next the trimmer is put into use.

9 will stand of itself in this position as the forward edge of board 1 is formed to bear against strip 3 as shown in that figure.

While the invention has been described and illustrated in its several preferred embodiments, and has included certain details, it should be understood that the invention is not to be limited to the precise details herein illustrated and described since the same may be carried out in other ways falling within the scope of the invention as claimed.

I claim:

1. A cutting board assembly comprising a base member, a board to support sheet material to be cut, pivot means on said base member supporting said board for movement of one edge about an axis, a first shearing blade supported fixedly relative to said board adjacent said one edge thereof and spaced above the supporting surface of said board to permit sheet material to be cut to be positioned between said board and said shearing blade, and a second shearing blade mounted substantially stationarily relative to said base adjacent said one edge of said board for shearing relationship with said first blade from below the latter, in combination with clamping means comprising an elongated member supported at opposite ends by said board parallel to and adjacent said one edge thereof for movement of at least one edge surface of said member 'toward and from said board when said board is moved in opposite pivotal directions, and means arranged to coact with said clamping member and operable upon movement of said board first occurring relative to said second blade to actuate said clamping member and move at least said edge of said clamping member into clamping engagement with a sheet upon said board and clamp the same to said board adjacent said first blade to prevent relative movement between said sheet and board while being sheared by said blades.

2. The cutting board assembly set forth in claim 1 further characterized by one of the surfaces on said board and clamping member between which sheet material is clamped to be sheared has friction means afiixed thereto for non-damaging engagement with a sheet of material when clamped between said surfaces, thereby to facilitate the clamping of a sheet of material between said surfaces.

3. The cutting board assembly set forth in claim 2 further characterized by said friction means being secured to the upper surface of said board adjacent said one edge thereof.

4. A cutting board assembly comprising a base member, a cutting board member hingediy connected at one edge of said base member for pivotal movement of the opposite edge of said board member toward and from said base member, a first shearing blade connected to said board member adjacent and parallel to said opposite edge thereof and spaced above the supporting surface of said board to permit sheet material to be cut to be positioned between said board and said shearing blade, a second shearing blade supported by said base member and extending upward therefrom for shearing cooperation of the upper edge thereof with said first shearing blade, in combination with clamping means comprising an elongated clamping member pivotally supported adjacent the opposite ends thereof by said board member parallel to and adjacent said one edge thereof for movement of said clamping member toward and from said board member, actuating means connected to said clamping member and operable upon initiation of movement of said board member toward said base member to move said clamping members toward said board to clamp a sheet upon said board and hold the same firmly clamped thereon relative to said first blade While being sheared by said blades.

5. The cutting board assembly set forth in claim 4 further including additional support means fixed relative to said board and engaging said clamping member intermediately of the opposite ends thereof to insure firm 1t) clamping by said member substantially evenly along the entire length thereof.

6. The cutting board assembly set forth in claim 5 further characterized by said additional support means being fixed to and supported by said first shearing blade intermediately of the ends thereof, said blade also extending substantially perpendicularly to the plane of said cutting board member, thereby affording rigidity to said additional support means to prevent displacement thereof away from said board member incident to the clamping operations of said clamping member.

7. A cutting board assembly comprising a base member, a cutting board member hingedly connected at one edge to said base member for pivotal movement of the opposite edge of said board member toward and from said base member, a first shearing blade connected to said board member adjacent and parallel to said opposite edge thereof and spaced above the supporting surface of said board to permit sheet material to be cut to be positioned between said board and said shearing blade, a second shearing blade supported by said base member and extending upward therefrom for shearing cooperation of the upper edge thereof with said first shearing blade, in combination with clamping means comprising a clamping blade supported pivotally at opposite ends by said board member parallel to and adjacent said one edge thereof for tilting movement of said blade about the axis thereof to move one edge of said blade toward and from said board member, actuating means connected to said blade, and cam means supported substantailly stationarily during use relative to said base member and engageable with said actuating means upon initiation of movement of said board member toward said base member, thereby to tilt said clamping blade into clamping engagement with a sheet upon said board and hold the same clamped upon said board member and relative to said first blade while being sheared by said blades.

8; The cutting board assembly set forth in claim 7 further characterized by said actuating means for said clamping blade comprising an arm connected at one end to said clamping strip and extending radially from the axis thereof, and a roller pivotally mounted thereon for engagement by said cam means to effect tilting movement of said clamping blade.

9. The cutting board assembly set forth in claim 8 further including a second roller, and pintle means fixed relative to said board member and rotatably supporting said second roller adjacent said roller upon said actuating arm, said cam means being elongated and arranged to project between said two rollers, the second roller serving as a backing roller for said cam means.

10. A cutting board assembly comprising a base memher, a cutting board member hingedly connected at one edge to said base member for pivotal movement of the opposite edge of said board member toward and from said base member, a first shearing blade connected to said board member adjacent and parallel to said opposite edge thereof, a second shearing blade supported by said base member and extending upward therefrom for shearing cooperation of the upper edge thereof with said first shearing blade, in combination with clamping means comprising a clamping strip supported pivotally at opposite ends by said board member parallel to and adjacent said one edge thereof for tilting movement of said strip about the axis thereof to move one edge of said strip toward and from said board member, actuating means connected to said strip, and cam means supported by and extending upwardly from said base member and comprising an elongated member curved in an arc about the axis of the hinged connection of said base and board members, the upper end of said cam means having a cam surface engageable with said actuating means upon initiation of movement of said board member toward said base member, thereby to move said actuating means to tilt said clamping strip into clamping engagement with a sheet 1 1 upon said board and hold the same immovable relative to said first blade while being sheared by said blades.

11. The cutting board assembly set forth in claim 7 further characterized by said cam means comprising an elongated member pivotally connected at one end to said base member andextending upwardly therefrom in operative position to engage said actuating means for said strip, said cam member being movable pivotally against said base member and said second shearing blade also being hingedly connected at the lower edge thereof to said base mem ber, whereby said cam member and second blade may be folded against said base member and thereby permit said board member to be moved toward said base member to effect a compact arrangement of said assembly when not in use.

12. A cutting board assembly comprising a base member, a cutting board member hingedly connected to said base member at one edge for pivotal movement of the opposite edge of said board member toward and from said base member, a first shearing blade connected to said,

board member adjacent said opposite edge thereof and parallel thereto, said blade being substantially perpendicular to the plane of said cutting board member and the shearing edge ofsaid blade being close to said board but spacedfrom the supporting surface thereof to permit sheet material to be positioned between said board and shearing blade to be cut, a second shearing blade extending transversely to the plane of said board member adjacent said opposite edge thereof and pivotally connected at one end to said base member and extending upwardly therefrom, the upper edge of said second blade being sharpened to comprise the cutting edge,'rneans engageable with said second blade and operable to urge the upper cutting edge by said board and first blade may be moved a limited distance toward the cutting edge of said second blade prior to shearing engagement to develop kinetic energy and said second blade is aligned Withsaid first blade while so moving, a clamping member movable toward and from said board adjacent and substantially parallel to said first blade, and actuating means interengaging said clamping member and operable upon movement of said board member toward said'base member to move said clamping member in sheet-clamping relationship relative to said board member to prevent a sheet from moving relative .to said first shearing blade while being sheared by said blades.

13. A cutting board assembly comprising a board to support sheet material to be cut on theupper surface thereof, base means, means guiding said board for movement of one edge towardand from said base means, a first shearing blade supported fixedly relative to said board adjacent said one edge thereof, and spaced above said upper surface of said board to permit said sheet material to be positioned between said board and shearing blade, and a second shearing blade mounted substantial- ,ly stationarily relative to said base adjacent said one edge of said board for shearing engagement by said first blade means interengaging said clamping member and operable upon the initiation of movement of said board toward said base to move said clamping member into clamping engagement with a sheet of material when placed upon said board to hold said sheet clamped to said board adjacent said first blade to prevent relative movement between said sheet and board while being sheared by relative movement between said blades.

References Cited in the tile of this patent UNITED STATES PATENTS 596,530 McCoy Jan. 4, 1898 1,167,435 Robertson et al Jan.11, 1916 1,730,718 Bosch Oct. 8, 1929 1,885,169 Altvater Nov. 1, 1932 1,913,028 Haveles June 6, 1933 2,071,055 Alf Feb. 16, 1937 2,097,363 Bowie Oct. 26, 1937 2,120,329 Henneke June 14, 1938 2,259,351 Oberholser Oct, 14, 1941 2,351,093 Beckley June 13, 1944 2,516,602 Snyder July 25, 1950 2,517,362 Thompson Augv 1, 1950 2,553,096 Konchan May 15, 1951 2,634,454 Attenburger i i Apr.'14,"1953 2,767,735 Darling Oct. 23, 1956 2,959,806 Stewart Nov. 15, 1960 FOREIGN PATENTS 8,707 Great Britain June 12, 1915 123,967

. Great Britain Mar. 13, 1919

Claims

1. A CUTTING BOARD ASSEMBLY COMPRISING A BASE MEMBER, A BOARD TO SUPPORT SHEET MATERIAL TO BE CUT, PIVOT MEANS ON SAID BASE MEMBER SUPPORTING SAID BOARD FOR MOVEMENT OF ONE EDGE ABOUT AN AXIS, A FIRST SHEARING BLADE SUPPORTED FIXEDLY RELATIVE TO SAID BOARD ADJACENT SAID ONE EDGE THEREOF AND SPACED ABOVE THE SUPPORTING SURFACE OF SAID BOARD TO PERMIT SHEET MATERIAL TO BE CUT TO BE POSITIONED BETWEEN SAID BOARD AND SAID SHEARING BLADE, AND A SECOND SHEARING BLADE MOUNTED SUBSTANTIALLY STATIONARILY RELATIVE TO SAID BASE ADJACENT SAID ONE EDGE OF SAID BOARD FOR SHEARING RELATIONSHIP WITH SAID FIRST BLADE FROM BELOW THE LATTER, IN COMBINATION WITH CLAMPING MEANS COMPRISING AN ELONGATED MEMBER SUPPORTED AT OPPOSITE ENDS BY SAID BOARD PARALLEL TO AND ADJACENT SAID ONE EDGE THEREOF FOR MOVEMENT OF AT LEAST ONE EDGE SURFACE OF SAID MEMBER TOWARD AND FROM SAID BOARD WHEN SAID BOARD IS MOVED IN OPPOSITE PIVOTAL DIRECTIONS, AND MEANS ARRANGED TO COACT WITH SAID CLAMPING MEMBER AND OPERABLE UPON MOVEMENT OF SAID BOARD FIRST OCCURING RELATIVE TO SAID SECOND BLADE TO ACTUATE SAID CLAMPING MEMBER AND MOVE AT LEAST SAID EDGE OF SAID CLAMPING MEMBER INTO CLAMPING ENGAGEMENT WITH A SHEET UPON SAID BOARD AND CLAMP THE SAME TO SAID BOARD ADJACENT SAID FIRST BLADE TO PREVENT RELATIVE MOVEMENT BETWEEN SAID SHEET AND BOARD WHILE BEING SHEARED BY SAID BLADES.