US2275410A

US2275410A - Automatic adhesive sheet dispenser

Info

Publication number: US2275410A
Application number: US380116A
Authority: US
Inventors: Arthur A Anderson; Ralph H Munson
Original assignee: Minnesota Mining and Manufacturing Co
Current assignee: 3M Co
Priority date: 1941-02-24
Filing date: 1941-02-24
Publication date: 1942-03-10
Anticipated expiration: 1959-03-10

Description

March 10, 1942; A, ANDERSON ET AL 2,275,410

AUTOMATIC ADHESIVE SHEET DISPENSER Filed Feb. 24, 1941 3 Sheets-Sheet l March 10,19 A. A. ANDERSON ET AL AUTOMATIC ADHESIVE SHEET DISPENSER 3 Sheets-Sheet 2 Filed Feb. 24, 1941 4 March 10; 1942.

A. A. ANDERSON ET AL AUTOMATIC ADHESIVE SHEET DISPENSER Filed Feb 24, 1941 5 Sheets-Sheet 5 Eva/anions normally tacky adhesive Patented Mar. 10, 1942 Arthur A. Anderson,

County, and Ralph H. Munson, assignors to Minnesota Mining ing Company, St. Paul, Minn.,

Delaware 7 Rose Township, Ramsey St. Paul, Minn., & Manufactura corporation of Application February 24', 1941, Serial No. 380,116

11 Claims; (Cl. 16

This invention relates to a tape or sheet dispenser, and particularly to a dispenser for normally tacky or pressure-sensitive adhesive sheeting in roll form, such adhesive tape having a paper or cloth backing, or a backing of a cellulosic film, for example, coated on one side with a which is adherent without the necessity of activation by water, solvents or heat, and which can be unwound from rolls thereof without transfer or offsettingof the adhesive, due to the highly cohesive nature of the adhesive.

One problem in dispensing pressure-sensitive adhesive tape from a roll thereof is the difliculty of unwinding the tape and making it available in' accurately measured predetermined v unit lengths ready for use. 7

Without beinglimited thereto, the presentinvention provides a dispenser:

Which accurately measures and thrusts out a predetermined length of pressure-sensitive adhesive tape in position ready for grasping and severance, with its adhesive portion free'from contact with any object except at its inner end;

Which is power driven and entirely automatic so that the only necessary manual operation is the one single-handed manual actpof'grasping and severing the thrust-out portion, such act of severing roviding the activating impulse that sets the machine in motion for measuring and ment that responds to movement of the tape during the severing operation.

According to the present inv out adhesive tape maybe severed by drawing it against a substantially fixed blade, such blade however being slightly movable (without failing to remain fixed sufliciently to perform its severing function) and such blade being connected with the ,power control in a manner such that the power will be turned on either by the movement of the blade that occurs when the previously projected portion of the tape is drawn against the blade, or by the movement of the blade when the blade moves back into starting position after the tape has been severed and removed.' Thus the present invention provides an automatic power drive penser described in our copending application particularly where it 0 the units to be sealed or labele thrusting out the next length ready'for grasping and severing;

Which reduces the amount of power required to drive the machine and which reduces the time consumed by an operator in providing himself with a piece of tapeready'for application;

Which lends itself tense in industries where the sealing or labeling of packages, bottles,- envelopes, etc., must be fast, cheap and long-continuing in connection with methods;

Which can measure the dispensed lengths very accurately so as to be suitable for dispensing very long lengths (large rolls) of label tape which is printed to form a series of labels, such as airmail stickers, package or bottle labels,etc.;

Which can be easily adjusted to vary the predeterminedunit length of tape within 'a substantial range, and which can be operated to 85 Figures 2,

assembly line per 'wheel, arm showing stripper Serial No. 373,954, since issued as Patent No. 2,233,361 on February 25, 1941.

The machine that is described and illustrated herein asan example of an emobdiment of the present invention is a portable, electric power driven, automatic, pressure-sensitive adhesive tape dispenser, suitable for use in stores or factories or wherever packaging or labeling is done, is done in quantities such as where packaging is done according to the general plan of assembly line methods, 1. e., where d by hand are carried past the operator on rapidly moving belts.

In the accompanying drawings:

Figure 1 is aperspective view of the front and left side.

and 4 are vertical cross-sections of the draft wheeltaken on the lines 2-2, 33

and 4-4, respectively, in Figure 8.

Figures-5 and 6 are tions, .respectively, of the upper end of the stripand guide wheels.

Figure 7 is a horizontal cross-section of the draft wheel taken on the .line 1- -1 in Figure 8. Figure 8 is a vertical cross-section of the machine taken, on the line 8-8 in Figure 9. Since I the line 8-8 cuts through only the casing, Figdispense tape accurately measured in lengths which are multiples of the unit length.

According to the present invention, a power driven dispenser is provided, and is made automatic by use of a control system having aneleure 8 may be regarded as a front elevation or the machine with thefront wall of the casing removed.

Figure 9 is half of the machine taken Figure 8. i

Figure 10 is a horizontal cross sectio'n of a pora vertical cross-section of the front on the line 99 in tion'of the interior taken on the line III-40 in ention the thrustfor the .type of disleft side and front eleva- Y Figure 8 and includes a plan view of the crank arm assembly.

Figures 11 is a horizontal cross-section of the crank arm assembly taken on the line in Figure 8.

Figure 12 is a vertical cross-section of the crank arm assembly taken on the line |2|2 in Figure 10.

Figure 13 is a vertical cross-section of a portion of the interior taken on the line |3|3in Figure 8 and includes a right side elevation of the switch activating mechanism and the switch, and includes a diagram showing the switch connected in series with the motor.

To the base 3| is rigidly but removably attached the upright supporting plate 32 by means of the screws 33. The base 3| and upright 32 may be cast in a single piece if desired. The base and the upright have various bosses at proper points to which are attached the various parts of the machine, all of said parts being supported directly or indirectly by the base 3| and upright 32. Base 3| may be of heavy weight to prevent movement of the portable machine during use.

The supply roll R- of pressure-sensitive adhesive tape S is carried on the tape roll holder drum 34 on the left side of the upright 32 towards the rear of the machine. The mechanism for withdrawing the tape from the supply roll and dispensing it in lengths ready for use is on the left side of the upright 32 towards the front. On the right side of the upright 32 is the automatic power mechanism assembly which activates the said withdrawing and dispensing mechanism.

The machine may be wholly enclosed in a case in which there may be an appropriate opening through which the projected portion of the tape is thrust by the machine; or, as shown in the present embodiment, the power mechanism alone may be enclosed with a three-sided case 35 which fits against the upright 32 and whose lower portion 35a is attached to three edges of the base 3|. Case 35 is fastened to its lower portion 35a by hinges 36 so that case 35 may be swung to the right and downwardly to expose the mechanism whenever desired. When in closed'position, the case 35 is held in place against the upright 32 by a handle and catch, not shown, which engages with the upper part of upright 32.

Tape holder drum- 34 may be of a size to receive the standard commercial sizes of rolls of pressure-sensitive adhesive tape such as that sold under the trademark Scotch," for example, but if desired, the machine may be provided with several interchangeable drums of varying sizes. The periphery of tape drum 34 is provided at intervals with ridges 34a extending parallel to the drums axis so as to provide a tight fit between the drum and a roll of tape notwithstanding any possible slight variance in actual size of rolls that are used from time to time. The ridges also help to prevent slipping.

The screw-head 37 (Figure 1) is the head of an axle-bolt which pierces the upright 32 at right angles thereto and parallel to the base 3|. Tape drum 34 is journaled onto the axle-bolt so as to turn freely thereon between the head 31 and a flanged part so as to be stopped against length- Wise movement. The end of the axle-bolt is in threaded engagement with the upright 32, said engagement being sufficiently tight to make the bolt relatively rigid in the upright. The axlebolt may be turned by its screw-head 31 to permit adjustment of the tape drum 34 laterally in respect to the machine as a whole so as to adjust wheel 38 in proper R and projected through the machine by reason of. its temporary adherence to the periphery of the draft wheel 38 which is a part of the dispensing mechanism at the forward part of the machine. The tape may be led directly from the roll R to the draft wheel 38, or, as in the present embodiment, it may be led around the idler roller 39, thereby permitting a larger area of the tapes adhesive surface to contact the periphery of the draft wheel 38.

Draft wheel 38 is mounted torotate freely on shaft 40 which pierces the upright 32 at a point where the upright is reinforced on both sides by the bosses 32a. At its extreme right end, shaft 40 also pierces the small bracket 4|a which projects rearwardly from the right end of the large horizontal bracket 4|. Bracket 4| is rigidly fixed to the right side of upright 32 at a point slightly -forward (Figure 9) of the point at which shaft 40 pierces upright 32. The rib 4|b reinforces the large bracket 4| and helps to anchor it more firmly to upright 32. Bracket 4| and upright 32 may be cast in one piece if desired.

Shaft 40 is thus journaled into and supported by the upright 32 and the small bracket Ma, and it turns freely in respect thereto. Shaft 40 is preferably mounted with its axis at right angles to upright 32 and parallel with base 3| and with the axis of the tape supply V drum 34. It may be stopped, by means not shown, against lengthwise movement.

The periphery of draft wheel 38 to which tape S temporarily adheres as .it is being drawn through the machine, is straight knurled in lines parallel to its axis. A peripheral groove 38a is cut to lie in a plane perpendicular to the axis of wheel 38.

tapes contact with the draft wheels periphery and is positioned so as to leave on either side of the groove an area of knurled surface sufiicient to permit tape S to adhere to said knurled surface when the tape is positioned so that the small stripper wheel 42 contacts the tape. Groove 38a is of a width to admit the stripper wheel arm 44 without contact with draft wheel 38, and deep enough so that stripper wheel 42 may be inserted in the groove to a depth of about half the diameter of stripper wheel 42.

In order to augment the outward thrust of stripper wheel 42 after the advancing tape is lifted off the peripheral surface of the draft wheel 38, an auxiliary stripper wheel or guide wheel 43 may be employed, as shown in the present embodiment (Figures 3, 5 and 6), but wheel 43 may be omitted, if desired.

Stripper wheel arm 44 is held in place by being 00 shaped at its lower end to register with the boss 32b (Figure 3) which is a part of upright 32 and which projects outwardly from the left side thereof. The arm 44 is pierced at itslower end with holes to admit screws 45 which are in threaded engagement with the boss 32b. The screw holes in the stripper wheel arm 44 are sufiiciently large topermit adjusting the position of arm 44 to bring the stripper wheel 42 into proper position relative to the severing means B and to the draft wheel 38, after which screws 45 are tightened so that arm 44 is held rigid by the pressure of the screwheads on its left side.

At its upper end the stripper wheel arm 44 is split to form two arms 44a, having between them 7-; sumcient space to permit stripper wheel 42 and It limits the transverse extent of the ever position through the clutch guide wheel 43 to turn freely on the pins or axles 42b and 43b, respectively, each. of which are iournaled in arms 44a (Figures and 6), Stripper wheel 42 is preferably quite small in diameter, as compared with the draft wheel, and is shaped so that its periphery 42a is very narrow or knife-like. It is located a substantial distance forwardly tacts the draft wheel. Guide wheel 43 may be similar in size and shape to stripper wheel 42' and its location in relation thereto may be in whatwill enable it best to perform the of points'at which the tape first contion shown in Figure 2, the roller is wedged tight and cannot turn. In actual practice the taper of the spaces is such that only a slight change of position of the" roller will either wedge the roller function of guiding the tape farther away from the machine as the tape is being projected outwardly into position for grasping and severing.

A fixed transverse shearing blade or knife B is located tangentially and in close proximity tothe periphery of draft wheel 38 and with-its edge pointed toward, and in per wheel 42, so that the tape S passes under the of the draft wheel (Figure 3). tape is projected outwardly by the stripper wheel 42, and can be severed by grasping the end of the tape and pulling the tape against the blade. The blade or knife preferably has a straight edge as distinguished from a sawtooth or serrated edge, permitting a clean cut. The knife edge is preferably only sufficiently far from draft wheel 38 to permit free movement of the wheel when its periphery is carrying a thickness of tape, and sufficiently above stripper wheel 42 to permit the tape to be bent by stripper wheel 42 outwardly away from draft wheel 38, andsufllciently close to stripper wheel 42 so that the tape is stripped ofi directly after it passes the knife edge.

The blade B is a blade that is substantially fixed in relation to the material it cuts in that it functions by the material being drawn or forced against the blade rather than by the blade being moved through the material; but in relation to the machine the blade is movable, and the manner in which this movement'serves to activate the automatic power mechanism that projects the tape through themachine will be hereinafter described.

Draft wheel 38 is driven by the power wheel 46 cam 46b which is rigidly attached to the wheel 46. The side of the draft wheel 38 which is adjacent to power wheel 48 is cut away in the form of a deep and wide concentric groove designed to receive cam 46b so that draft wheel 38 may turn freely in close proximity to power wheel 46 without contacting cam 46b.

Similarly, there is rigidly attached to side plate 4'! the clutch cam 41a. Also the adjacent side of the draft wheel 38 is cut away to receive the cam and to permit wheel 38 to turn freelyin close proximity to plate 41 without contacting cam 41a. Side plate 41 is rigidly attached to boss 32a and is therefore rigid in relation to upright32.

Referring to Figure 58a between the cam 46b and the. inside rim of draft'wheel 38 are of a size to receive

rollers

48, 48 and 58. .When any one of the rollers is located in relation to its space-as is roller 48 in Figure 4, such roller 'is free to turn. But the spaces 48a. 48a and Wit-taper so that when a roller is located as are

rollers

48 or 58 in Figure 4, it is wedged tight between cam 46b and wheel 38 and cannot turn; Similarly, the space Sla (Figure 2) 'between cam 41a and rim of wheel 38 permits roller 5! to turn freely. But the space tapers so that when roller 6! is located in the particular posiclose proximity to, stripor render it free to turn- A greater distance. is shown in the drawings for sake of clarity" Referring to Figure 4, when the mechanism is motionless, at least one of cam 46b and wheel 38 (like roller when power wheel 46, and with it cam 46b, is turned clockwise, draft wheel 38 is moved in unison therewith. But when power wheel 46. and with it cam 46b, is moved counter-clockwise, all the

rollers

48, 43 and 58 are rolled away from their wedged position to where they are free to turn so that no turning impulse is applied to edge and then over the stripper wheel a draft wheel 38.

To insure against any slight turning of wheel 38 in a counter-clockwise direction, the clutch cam 41a and its roller 5|, as previously described, are provided. If the working of the parts or snap of the tape or other cause tends in any way to turn the draft wheel counter-clockwise (Figure 2), the roller 5|, being held by gravity in wedged position in its space, instantly brakes the draft wheel. But when draft wheel 38 is turnedwheel 46, the roller Sla where it is free it cannot brake clockwise by force of power 5| is moved toward its space to turn, and being free to turn, the wheel 38.

If there were any backward rotation of draft wheel 38, accuracy of measurement of dispensed lengths would be lost; also it would-cause spoilage of the tape due to overlapping of adhesive coated surfaces upon each other.

Instantaneous braking of the. draft wheel 38 against backward turning, as contrasted'with the Likewise, since at least one of the 4, the,

spaces

48a, 48a and delayed braking action secured by other one-way driving mechanisms, such as a ratchet, provides positive prevention of even the slightest shortening of the length of tape that has been projected. three

rollers

48, 48 or 58 is always in wedged position, the draft wheel 38 turns instantly as soon as power wheel 46 is turned, so that the length of tape projected will coincide precisely with the amount of turn of the power wheel 46, the length of whose turn is measured and controlled accurately as hereinaft-er described.

Accuracy of measurement is particularly desirable in the dispensing of label tape which is printed to form a series of labels, such as airmail stickers. The mechanism herein described is inherently of a kind that minimizes inaccuracies and the accumulation of inaccuracies and permits the reduction of backlash to a negligible amount.

Power wheel 46 which turns draft wheel 38 is actuated by the shaft 48. The set screw 52 in the hub 46a of the power wheel 46 when tightened renders the power wheel 46 fixed in relation to the shaft 48 so that wheel 48 is turned by and in unison with the shaft 48.

As previously described shaft 48 is supported by the upright 32 and the small bracket 4la, being jcurnaled therein. Shaft 48 rotates freely in 1 relation to upright 32 and bracket 4la. At a point approximately midway between the upright 32 and th bracket 4la, a gear or pinion 63 is the three rollers will --positioned to move in an approximately vertical direction. Rack 54a is rigidly fixed to the rack shaft 54 with the longitudinal axes of the rack and shaft parallel. Rack shaft 54 is slidably mounted inside the rack guide 55, the two parts being fitted one within the other so that the rack shaft 54 can have no movement in relation to the guide 55 except along its own longitudinal axis.

The vertical rack guide 55 is supported by the horizontal draft wheel shaft 40. At a point approximately midway of its length the guide' 55 has two lugs or brackets 55a and 55b which project forwardly from the guide. The shaft 40 pierces these two brackets and is journaled therein so that shaft 40 turns freely in relation to the guide 55. The pinion 53, previously described, turns in unison with the shaft 40 between the two brackets 55a and 55b. Being thus mounted on the shaft 40, the guide 55 is free to turn about the shaft's axis and to move back and forth in response to the movement imparted to it by the operation of the lever or crank assembly below (hereinafter described) while permitting the rack 54a to be enmeshed with its pinion 53 at all times.

Rack shaft 54 is actuated in a manner to retate the pinion 53 by having its lower end rotatably attached to,a lever or crank arm 56, said rotatable attachment being adjustable along the length of the crank arm so as to vary the stroke of the rack.

Referring now to Figures 10, 11 and 12, a crank pin bearing 51 is provided with a threaded verti:

cally extending aperture to receive the threaded lower end portion 54b of the rack shaft 54, they crank pin bearing 51 being rigid in relation to the shaft 54. However the pin bearing 51 does not bear directly on the crank pin-bolt 58 but on a crank pin sleeve 59 which surrounds pin-bolt 58. Sleeve 59 is a few thousandths of an inch longer than the thickness from left to right (Figures 11 and 12) of. crank pin bearing 51 so that when the nut 60 is tightened, the pressure of the wash-1 ers 6| and 62, as they are forced toward each other, will be exerted on the sleeve 58 and not on the bearing 51, thereby leaving the crank pin- 'bolt 58 free to turn in the bearing 51.

The lever or crank arm 56 is rotated by being rigidly fixed on the end 01' power shaft 58 at right angles thereto, the shaft 68 having an end portion 63a in threaded engagement with crank arm 56.

Crank arm 56 is slidably mounted the headed end of the crank pin-bolt 58. Slot 56a is positioned so that when the crank arm 56 is rigidly mounted on the power shaft 63, the pin-bolt 58 will always be parallel with the shaft 63 at whatever point the pin-bolt 58 is moved within the slot 56a along the length of the crank arm 56.

In order to adjust the length of stroke of the lever or crank arm 56 that is exerted on the rack shaft 54, the shaft of pin-bolt 56 is pierced. near its head 58a, by adjustment screw 65. The

has a lengthwise slot 56a, 1- V shaped in cross-section (Figure 12), into which screws 19 and 19' may be rendered through which the collar justment screw 65 is made in the crank arm 55 may be inserted when the parts are being assembled and through which the set-screw 66 may be reached to be tightened.

Washer 62 onpin-bolt 58 is equipped at its top with a pointer or indicator 62a. calibrations 56c are marked on the crank arm 56 in a position to enable'the pointer to show how long the effective stroke of the lever or crank arm 56 will be and thereby to show of tape will be dispensed at each stroke.

The horizontal power shaft 53 is turned through the coupling 1| bythe electric motor M which is equipped with reduction gears (not shown). Shaft 63 is journa-led into the bearing 12a which. is a part of the'upwardly extending bracket 12 which is fastened to boss li'la on the base 3|.

The motor M is turned on and off by a reset "micro switch" 13 which is shown as being mounted on the bracket 12 above the power shaft 63, with the on switch-pin 13a on thetop side of the switch and the "off pin 13!) on the under side of the switch. The leaf spring 130, fastened to the underside of the switch 13, extends below and beyond the pin 13b to where it on the coupling on power to press the off pin 13?) off. By a reset switch two pins, one

shaft 63 sufficiently and turn the switch threaded engagement therewith and which is held rigid in relation thereto by the lock-nut 18.

The knife arm 11 extends through an aperture in the upright 32 and at its outer end has rigidly but removably fixed thereto the severing means gagement with the two arms of the U-shaped yoke He that extends upwardly from the horizontal bracket 4|, previously described. Set

tion to the yoke 4| 0 by lock-nuts and 80.

The balance arm 17b is with each other for a substantial distance on Mode of operation The balance weight 8| is moved to the right the operator what length fixed in relarigidly fixed to knife arm 71 and bent to render both arms parallel ing cycle, the nut 60 onthe crank against the knife .as

. by the shaft 63,

or left by turning it on its arm 11b and the contact screw 16 is turned up or down (and fixed in position by the lock-nut 18) until the knife arm 11 is supported principally by the pivot points on its cross arms 11a but also by the contact screw 16 resting on the switch plunger 16, which, in turn rests on the switch-pin 1311 that is supported by the spring inside the switch.

The adjustment or balance of the knife arm ll may be such that the upward pullof the tape against the blade B when severing the tape is suflicient to depress the on switch-pin 13a of the reset switch I3, and such that after the tape is severed and the upward pull on the knife B is removed, the knife arm I1 can be returned to its normal position by the upward impulse provided by the on" point 13a of the switch 13 resetting itself. Also the adjustment may be such that the blade B need move upwardly and downwardly only a very slightdistance since the severing is by means of drawing the material against a substantially fixed blade rather than by moving a blade through substantially fixed material and since too great a movement of the blade during severance mightdraw the unprojected portion of tape, which is in contact with the draft wheel 38, out of alignment. In one machine that we have made embodying the present invention, the movement of the blade B did not exceed .015 inch. This precise distance, however, is not critical and may vary within the limits indicated above.

To adjust the machine so that it will project the desired length of single dispenspin-bolt 58 is loosened and the head 55a of the adjustment screw 65 is turned in the desired direction to slide the crank pin-bolt 58 along its slot 58a lengthwise of the crank arm 56 until the distance from pin 58 to power shaft 63 (as shown by the pointer 820. on the scale 560) is such that one full upward stroke of the rack 54b will thrust out the desired length of tape beyond the knife edge, whereupon the nut 60 is tightened to fix the stroke at the selected length.

Supply roll R of pressure-sensitive adhesive tape 5 is mounted on the drum 34, and by tuming the screw-head 31 the drum may be adjusted laterally to align it directly behind the draft wheel 38, so that when the tape is threaded through the machine it will contact the stripper wheel 82.

The tape S, being wound on its adhesive side facing inwardly, is led from roll R around the idler roller 39 (or directly from the roll R without going around roller 39) over draft wheel 38, the adhesive side contacting the draft wheels periphery, until the forward edge of the tape extends an inch or more beyond'the cutting edge of the blade B (Figures 1 and 3) The length of tape that extends beyond the cutting edge of the knife B is then grasped by the operator and severed by pulling it upwardly against the cutting edge. This upwardpressure described above, causes the thereby starting the motor M which turns power shaft 63 counterclockwise (Figure 9). Crank arm 56 is turned drawing the rack'shaft 54 and rack a downwardly so that pinion 53 also turns the roll R with switch 13 to be turned on,

counter-clockwise and continues so to turn until the crank pin 58 reaches the point in its circular path at which its moveme t ceases to impel the rack shaft 54 downwardly and begins to move it upwardly. v

During the downward stroke of the rack 54a, pinion 53 rotates its shaft All counter-clockwise and with it power wheel 46 andcam 461). But aspreviously described, by reason of the

rollers

48, 49 and 50, no motion is conveyed to draft wheel 38 when wheel 66 movescounter-clockwise. Also, as previously described, draft wheel 38 is counter-clockwise or backlocked against any clutch cam lla on side plate ward movement by 41 and by roller 5!.

The upward stroke, which immediately follows the downward stroke, of rack 54a turns the pinion 53 clockwise (Figure 9) through of turn of the crank arm 58. Since power wheel 56 and the pinion 53 are rigidly fixed to the draft wheel shaft 40, the wheel 46 and its clutch cam 4% move clockwise (Figure 4) in unison with the pinion. The cam 46?), through at least one of the

rollers

48, 49 and 5B (in a manner previously described), imparts the impulse without lag or loss of motion to the draft wheel 88 so that draft wheel 38 also turns clockwise in unison with the pinion 53.

The adhesion of the tape S to the draft wheels periphery is sufficient to withdraw the tape from the roll R and project it beyond the cutting edge of the severing means B (Figures 1 and 3).

Normally, the tape would continue to adhere to the draft wheel as the wheel turns, but just as the tape moves beyond the knife edge, the tape meets the stripper wheel s2 and is forced off the peripheral surface of the draft wheel and directed outwardly away from the machine.- As stripper wheel 42 is the forwardmost part of this section of the machine, and since the tape has some degree of stiffness, the advanced portion of tape projects clear of to be readily jgrasped.

If atmospheric conditions curl the tape or if other conditions under which the machine is used make it desirable to augment the outward guidance of projected tape, an extra guide wheel or roller of small diameter 43 may be rotatably held forwardly of the stripper wheel 62 and in line therewith (as shown in the present embodiment) to guide the projected tape outwardly still farther away from contact with the machine.

Straight knurling crosswise of the draft wheel 38, among other functions, provides the wheel with greater traction upon the tape being re moved from the roll R, since the pull is in a direction tangential to the draft wheel 38. It also causes the wheel to exert less resistance to stripping ofi of the tape due to the limited contact area.

Just after the upward stroke of rack 54a has been completed and the draft wheel 38 has thereupon stopped its clockwise rotation, the cam I la on motor shaft coupling ll (Figure 13) comes into a position to lift the leaf spring 13c to press the switch-pin 13b upwardly enough to shut off the power. The motor will coast somewhat so that crank arm 56 (and with it pinion 53 and power wheel 48) will move counter-clockwise for a distance, but since crank arm 56 and the connected mechanism operated thereby may turn 180 before any dispensing movement (i. e. clockwise rotation) of draft wheel 38 takes place, a standard commercial gear reduction mechanism may be selected for use in connection with the motor of a size to produce a ratio that will give the motor the necessary coasting distance so as In the drawings (Figure 9) the rack 54a is the machine and in position duced during the severing is used generically to reduces the time that must be shown as having come to a stop at about the midint of its downward stroke. As previously described, during such downward stroke, the draft wheel 38 remains stationary so that the full projected length of tape S is still held out away from the machine ready to be, severed by pulling it diagonally up and across the blade B, such severing serving also to start the mechanism in motion through another cycle whereupon another length of tape is projected in readiness for severing. To do this, the operator need use only one hand. His other hand is free-at all times to hold the article to which the tape is to be applied. In fact, both hands are free most of the time since the only manual motion needed to operate the machine is to pick ofl' or tear oi! the successive lengths asrapidly as they are projected.

If a length of tape double, triple, etc., the normal length that the machine is then set to dispense, is desired, the operator may set the machine in motion by lifting the knife arm 11 slightly with. the hand or fingers rather than by the usual tearing off of the projected length. This may be repeated for as many cycles as is desired before finally severing the projected length. The illustrated machine may be readily used in this manner, but, if preferred, the knife arm 11' may be extended in length by fixing a thumb piece of convenient shape to its outer end,

In the illustrated embodiment, the initial or upward movement of the severing blade (pro operation) sets the driving mechanism into operation. ,It will be obvious, however, that the broad principle of utilizing movement of the severing blade can be employed in other ways. Thus a mechanism can be used in which the return motion of the blade is utilized to cause closing of the power circuit, so that the mechanism will not be set in motion until the severing operation is completed. However, in this latter connection, it may be pointed out that premature tape advance does not occur when the tape is severed in normal fashion in the dispenser shown in the drawings, since there is a short but sufiicient time lag between closing of the power circuit and long in proportion to It is to be noted that the present invention This is particularly desirable in 1' dispensers of pressure-sensitive adhesive tape bethe time available for unwinding, the less powerful the tation, what we claim is Y dispenser, driven means for purposesof illustration and not limias follows:

1. In combination in a motor operated tape advancing tape, tape severing means located to permit advanced tape to be cut oil, one-way intermittent driving means for the tape advancing means adapted to advance the tape an accurate predetermined amount followed by an idling period during which no tape advance occurs even with the motor in operation,

vention for length of tape has been advanced and during the idling period, and means for tiating operation of said driving means upon is automaticallyfollowed by the advance of an accurate predetermined length of tape into position for severing.

2. In combination in of a further predetermined length of tape into position for severing.

4. The device of claim 3 in which the tapeadvancing means is a draft wheel which moves the tape by reason of the tapes contact with its periphery.

5. In combination in a motor-operated tape spenser. a holder for a roll of the tape, a draft severing.

6. In combination in a motor-operated pressure-sensitive adhesive tape dispenser, a holder for a roll of pressure-sensitive adhesive tape,*a draft wheel located toremove tape from the roll and advance the sam and means for'stripping the tape from the draft wheel, a substantially fixed severing blade located to permit advanced tape to be severed by being manually drawn thereagainst and adapted to move in response thereto, one-way driving means for intermittently rotating the draft wheel an accurate predetermined amount and in one direction only, a crank and a reciprocable connection between the crank and the one-way driving means such that rotation of the draft wheel only occurs during. halfrotation of the crank, an electric motor drive for the crank, means for shutting oil the motor following completion of a tape-advancing half-rotation of the crank but prior to-return of the crank to tape-advancing-position, such that coasting of the motor will terminate before the crank has been moved to tape-advancing position, and

means for turning on the motor in response to movement of the severing blade, so that the severing of tape is automatically followed by the advance of a predeterminedlength of tape into position for severing.

7. A dispenser according to the claim' 6 in which the crank is adjustable to regulate the.

throw thereof and thus the length of tape dispensed.

8. In a pressure-sensitive adhesive tape dispenser, a holder for a supply roll of the adhesive tape, draft wheel means for withdrawing the adhesive tape from the roll by adhesive contact therewith, having a grooved periphery to limit the transvers extent of contact, one-way driving means, for rotating the draft wheel in a direction to withdraw the tape from its roll and means for preventing backward rotation of the draft wheel, a small rotatable stripping element extending into the grooved portion of the draft wheel and located a substantial distance forwardly ofthe point at which the tape first contacts the draft wheel, adapted to separate the tape from the draft wheel and direct it outwardly as the latter rotates, a substantially fixed transverse shearing blade located in close proximity to the periphery of the draftwheel and with its edge pointing toward, and in proximity to, said stripping element, so that tape passes under the shearing edge and then over the stripping element during rotation of the draft wheel and the tape can be severed by grasping the projecting part and pulling the non-adhesive backing against the shearing edge without substantial removal of the rearward portion of the tape from the draft wheel and without drawing it out of alignment, the said shearing blade being slightly movable without failing to-remain sufliciently fixed in relation' to the tape to perform its severing function, a'power driving means coupled tomatic power mechanism comprises an electric.

motor, a power shaft rotated by said motor and carrying a cam, a movable member carrying the shearing. blade, and a motor switch positioned so as to be turned on by the initial movement of said blade-carrying member in response to the pressure of the tape as it is being severed and so astobeturned off by said cam.

I 11. The device of claim 8 in which the automatic power mechanism comprises an electric the draft wheel.

motor, a power shaft rotated by said motor and carrying a cam, a movable member carrying the shearing blade, a motor switch positioned so as to be turned on'by the initial movement of said blade-carrying member in response to the pressure of the tape as it is being severed and so as to be turned off by said cam, a crank arm on said power shaft, a rack pivoted to said crank arm with the pivot being adjustable along the length of the crank armso as to vary the stroke of the rack, api'nion engaged by said rack so as to be rotated in alternate directions, said pinion turning the one-way'driving means for'rotating ARTHUR A. ANDERSON. RALPH H. MUNSON.