US2621433A

US2621433A - Motor-driven transfer tool

Info

Publication number: US2621433A
Application number: US97453A
Authority: US
Inventors: John R Boyle
Original assignee: Individual
Current assignee: Individual
Priority date: 1949-06-06
Filing date: 1949-06-06
Publication date: 1952-12-16
Anticipated expiration: 1969-12-16

Description

Dec. 16, 1952 .1. R. BOYLE MOTOR-DRIVEN TRANSFER TOOL.

2 SHEETS.SHEET 1 Filed June 6. 1949 IN V EN TOR. fa/Z72 12 50 BY 5 III Dec. 16, .1952 R BOYLE MOTOR-DRIVEN TRANSFER TOOL 2 SHEETS-SHEET 2 File'diune 6. 1949 Patented Dec. 16, 1952 UNITED STATES PATENT OFFICE 7 Claims.

The present invention is directed to an improved motor driven transfer tool for transferring markings from a transfer sheet to a receiving surface. The construction of tool dis closed in the present application is an improvement upon the motor driven transfer tool disclosed in my prior application, Serial No. 680,029, filed June 28, 1946, now issued as Patent No. 2,516,044.

As fully described in my above identified patent application, these motor driven transfer tools have a unique utility for transferring markings from a pliable transfer sheet to a surface intended to receive such markings. The principal field of utility is for transferring typewritten subject matter to mechanical drawings, tracings and the like. In practically every situation in which mechanical drawings, tracings, blueprints or the like are employed, it is usually desirable that these drawings, tracings or prints shall have legends or other descriptive lettering thereon, containing instructions about machining, drilling and finishing the parts, or containing instructions about the manner of assembling the parts, or bills of material used in the construction of the machine or part, or countless other legends too numerous to mention. In most instances, the drawing or tracing is too large to get into a typewriter, or it is too inconvenient to do so, and hence the general practice has been to place all of these legends on the original drawing or on the tracing by hand lettering operations. This is one of the most arduous, time consuming jobs in the ordinary drafting office, and adds greatly to the expense of the drawing or tracing. Because of the time and expense involved in these hand lettering operations, it frequently happens that insufficient descriptive data is applied to the tracing, or that necessary descriptive data is totally omitted from the tracing, rather than go to the trouble of putting it in by hand lettering. Also, in order to minimize hand lettering, lengthy descriptions, bills of material, etc. are frequently typewritten on separate sheets which are intended to be attached to the blueprints, but which often become detached and lost. In this regard, it is not feasible to paste typewritten sheets to a tracing because of wrinkling, different degrees of light transmission interfering with the making of prints, etc.

As fully described in my above co-pending application, I propose to type all of these legends, bills of material and the like upon transfer sheets of a size which can conveniently be inserted in the typewriter, and then to transfer this typewritten subject matter from the transfer sheets to the drawings or tracings by the use of my im proved motor driven transfer tool. The transfer sheet is inserted into the typewriter backed up with a carbon sheet or the like, but in the present situation the carbon side of that sheet does not face rearwardly toward a copy sheet, but instead faces forwardly so that as each type character of the typewriter strikes the transfer sheet a raised carbon impression of that type character is formed on the back side of the transfer sheet, with the type character in reverse. This transfer sheet is highly translucent, and might even be made transparent. After all of the subject matter has been typed out in this manner, the transfer sheet is laid upon the drawing or tracing with the downwardly projecting carbon characters in contact therewith. Because of the translucent or transparent nature of the transfer sheet, these carbon coated type characters can easily be placed in their proper positions relatively to the figures of the drawing to which they apply. With the transfer sheet now held in fixed position over the drawing or tracing, the motor driven transfer tool is moved across the top side of the transfer sheet in pressure engagement therewith for effecting a transfer of each carbon coated character from the transfer sheet to the top side of the drawing or tracing.

The success of the method is largely dependent upon the motor driven transfer tool. This tool comprises a rotary pressure head which is driven by a small electric motor, preferably at motor speed, such as in the neighborhood of 3400 R. P. M. The underside of this rotary pressure head carries a plurality of rolling balls, similar to small ball bearings, which have rolling contact with the top surface of the transfer sheet at this motor speed. These balls exert transfer pressure on the top side of the transfer sheet in the form of moving points of relatively small surface area and relatively concentrated pressure. Because of the high speed motion of the balls over the surface of the sheet a relatively large area can be covered very quickly notwithstanding the extremely small surface area of each ball. I preferably employ anywhere from seven to ten balls in my improved rotary pressure head, but it will be understood that a greater number of balls may be employed, if desired. These are all capable of independent rolling motion on the surface of the sheet during the rotation of the motor driven pressure head.

One of the principal objects of the present invention is to obtain a substantially constant pressure of the rolling balls against the transfer sheet. Another object is to limit this pressure to a pre determined degree so as to avoid or minimize the likelihood of the rolling balls tearing the transfer sheet or stencil. This constancy of pressure and predetermined limitation of pressure are insured at all times as the tool is moved back and forth or around in circles on the transfer sheet, irrespective of the rate of this sliding motion and irrespective of how much downward pressure the operator may be exerting on the tool. My improved construction also prevents the possibility of the pressure head being cocked at an angle to the transfer sheet in the movement of the tool over the sheet. Thus, all likelihood of tearing relatively thin transfer sheets is thereby avoided. The use of relatively thin transfer sheets is desirable so as to obtain a substantial height of projecting type character extending from the back side of the transfer sheet. My improved construction also avoids any tendency of the transfer sheet to wrinkle up ahead of the tool as the tool is moved in one direction across the sheet, and it also avoids any tendency of the sheet to creep across the work surface.

Other features of the invention reside in an improved air cooled motor for driving the pressure head; and in an improved switch for controlling the motor.

Other obiects, features and advantages of the invention will appear from the following detail description of one preferred embodiment thereof. In the accompanying drawings illustrating such embodiment: 4

Figure 1 is the side elevational view of my improved construction of transfer tool;

Figur 2 is a plan view thereof;

Figure 3 is a bottom view showing how the slidable base plate substantially embraces the rotary pressure head;

Figure is a fragmentary, axial, sectional View showing the construction of the rotary pressure head and its mounting;

Figure 5 is a fragmentary, sectional view of the rotary pressure head and its mounting, on a larger scale;

Figure 6 is a longitudinal, sectional View of the improved switch, on a larger scale; and

Figures '7 and 8 are transverse, sectional views of the switch, on this same larger scale, Figure 7 showing the position of the parts in the open circuit position and Figure 8 in the closed circuit position.

The main body of the tool is preferably in the form of a casting iii, such as a die casting. This casting is preferably made of metal, although it might be composed of a plastic material. This casting comprises a relatively large flat bottom base H which is apt to have sliding motion the surface of the transfer sheet. As shown in Figure 3, the front end of this base plate portion i i is formed with horseshoe-shaped opening 52 which embraces or surrounds th major portion of the rotary pressure head IS. Extending upwardly from the rear portion of the base plate 5! is a handle portion 13 having a finger a erture l3 extending therethrough, to form a -onvenient hand-grip for holding and manipulating the tool. Projecting forwardly as integral of the handle portion i3 is a cylindrical mounting portion M in which is mounted electric motor i5. This motor drives the rotary pressure head it through the pressure controlling drive coupling if.

The electric motor l5 may be of any suitable type capable of operating at a substantially constant speed, preferably in the range of 3400 R. P. M. or so. If there is much likelihood of the tool being used in direct current localities, this motor can be of the universal type. Preferably, however, it is a shaded pole alternating current motor of substantially constant speed characteristics. The motor is set down into the bowl-shaped mounting ring is, with the outer cylindrical surface of the stator fitting down snugly within the mounting ring Is. The stator and rotor of the motor are indicated somewhat diagrammatically at 22 and 23, the details of these parts being dependent upon the type of motor employed. The motor shaft 25 carries a fan 25 for circulating cooling air through the motor structure. After the motor parts have been inserted into the mounting ring it, a cover shell 26 is assembled down over the top of the mounting ring and motor and is secured to the mounting ring I-l by cap screws 2?. This cover shell has openings 28 therein and the lower bowlshaped portion Hi of mounting ring It has companion openings 28' therein for passing the fan circulated cooling air. Tie bolts 25 extend down through the stator structure '22 and thread into tapped holes formed in the lower bowl-shaped portion at of the main casting for holding the stator 22 down against an internal shoulder 30 in the mounting ring 14.

The upper end of the motor shaft 24 has antifriction bearing support in a ball bearing 3| which is carried in a rubber grommet 32 mounted in the cover shell 25. The shaft extends down through a relatively large axial opening 33 in the bottom portion it of the mounting ring, and transmits driving torque to the rotary pressure head it through the pressure controlling coupling l'i. This lower end of the motor shaft 24 has bearing support in a ball or roller type of anti-friction bearing 34 which has its outer race seating in a rubber grommet 35 like the grommet 32. These two rubber grommets establish self-aligning bearing supports for the shaft and also produce a quiet construction. Downward thrust of the motor shaft is sustained by a shoulder 35 on the shaft bearing against the top ofthe inner race 34 of ball bearing as. Upward thrust is sustained either through the upper ball bearing 31 or through the engagement of the shaft against the cover shell 26.

Removably mounted upon the shaft 24 below the inner bearing race 34 is a pressure adjusting washer or shim 4! which is adapted to bear against another shoulder 42 formed in the shaft. Forced up over the lower end of the motor shaft is the pressure controlling coupling l7, preferably in the form of a rubber tube which has a firm press fit up over the lower portion of the shaft. The rotating pressure head It, carried by the lower end of this rubber sleeve ll, comprises a head portion [5a, in the bottom side of which is retained a ring of balls [6b. An axial boss portion I extends upwardly from the top of the head portion Isa and has a firm press fit within the lower end of the rubber sleeve 17. The motor shaft 24 is provided with a reduced lower end 49 which has a loose guiding fit within a bore I6d extending down axially in the boss [60 and head [6a. A ball retainer sleeve ll fits up over the head portion [5a and has an inwardly turned lower lip 48 adapted to retain the balls I 6b within the circular lower raceway 49. A similar ball retaining lip liie may extend outwardly from the inner edge of the ball raceway.

As shown in Figure 4, the parts are so proportioned or adjusted that the plane of the bottom surfaces of the pressure head balls |6b normally projects downwardly below the plane of the bottom surface of the base plate II, as indicated by the distance between the dotted lines :0. The thickness of the adjusting shim 4| determines the degree of this projection to. When the tool is pressed down against the back of the transfer sheet in the performance of a transfer operation, this rotating ring of balls is forced back upwardly until it is approximately in coincidence with the plane of the bottom surface of the sliding base. This upward displacement of the balls predetermines the degree of pressure that the balls will exert against the transfer sheet or work surface. Substituting a thicker shim 4| increases this working pressure, andsubstituting a thinner shim reduces it. Thus, it is impossible for the operator to bring more than a predetermined degree of pressure upon the rotating balls irrespective of how much downward pressure he exerts through the handle I3 upon the sliding base plate. This avoids or minimizes any tendency of the transfer sheet to be torn or wrinkled from pressure. The lateral flexibility of the resilient coupling ll also insures that the ring of balls will lie perfectly flat against the transfer sheet or work surface. This fiat engagement of the pressure head against the Work surface is also insured by the fact that the axis of the electric motor and pressure head is held at right angles to the bottom surface of the sliding base II.

In one typical embodiment of my invention, the displacement distance a: is approximately .040 inch, and the resulting ball pressure is approximately 1.5 pounds. However, this is not limitative. The side fingers of the horseshoe-shaped opening l2 in the base are in close proximity to the pressure head I6 (Figure 3), and practically eliminate any tendency of the transfer sheet to wrinkle or pile up in advance of the pressure head.

The tool is preferably provided with a switch 55 for starting and stopping the electric motor. This switch is assembled within a cored opening 56 formed at that part of the main casting I where the handle portion merges into the base plate I I. As shown in Figure 4, the full size of this cored opening 56 is extended out to the right, directly above the horseshoe-shaped opening I2, so that the switch assembly 55 can be inserted into the opening 56 through this right hand end. The other end of the cored opening has a reduced extension 5'! through which passes the electrical cord 58 and its insulated bushing 59. Extending entirely through the cored opening 56 from side to side'thereof is a cylindrical bore 6| for receiving the switch actuating rod or button 62. As shown in Figure 2, opposite ends of this switch rod button project from opposite sides of the casting, one end being pushed inwardly for closing the switch, the opposite end being pushed inwardly for opening the switch. The end which is pushed inwardly for closing the switch may be provided with a distinctive coloring, such as red, as indicated at 62'. As shown in Figures 6, 7, etc., the entire switch assembly 55 is mounted within a cylindrical fibre sleeve 64 which is adapted to have an endwise sliding fit into the cored opening 56 from the right hand end thereof. This insulating sleeve has diametrically opposite holes 65 in its left hand portion for receiving the transversely extending switch rod button 62. It will be evident that after the switch assembly has been inserted into the casting it is held therein by thereafter passing the switch rod button 62 through these openings 65; and that the switch assembly can be quickly and easily removed for repair or substitution by sliding the push rod button 62 transversely out through the openings 65. This is one of the features of my improved switch. The motor circuit is controlled by a pair of contacts 66 and 6! mounted upon

leaf springs

68 and 69. These are mounted upon a stack of insulating spacers H secured to the end portion of the insulating sleeve 64. A switch actuating lever 12 is supported above the switch springs 68 and 69 by the same screws 13 that mount the switch springs and insulating stack to the fibre sleeve 64. An insulating button 14 projects downwardly from the under side of the switch lever 12 for transmitting downward motion to the upper switch spring 68 for forcing the

contacts

66 and 61 together. The left hand end of the lever 72 has a downwardly sloping portion 15 formed with an inverted V-shaped ridge 16 defining sloping sides leading up to the apex of this ridge, as clearly shown in Figures 7 and 8. Formed in the under right hand side of the reciprocable switch rod button 62 is a scarf or notch 18. The sloping end 15 of the switch actuating lever extends crosswise through this notch 18, and bears against the top surface of this notch. This top surface is formed with two levels 19 and which are joined by a cam slope 8!. The switch is in open position when the switch actuating button is pushed to the left for bringing the upper level 80 into a position above the inclined lever portion 15; and the switch is actuated to its closed position when the switch rod button 62 is thrust to the right so as to cause the cam slope 8| to force the switch actuating lever end 15 downwardly to the point where the level 19 holds the switch actuating lever depressed. This depressing of said lever closes the

contacts

66 and 61. The lower level 19 has a slope for obtaining snap action of the switch button when pushed to the on position, and the switch also has a snap action when the button is pushed to the off position by virtue of the lever end 75 snapping upwardly to the higher level 80.

The ends of the notch 78 are formed with abrupt or right angle shoulders 62. These right angle shoulders normally prevent accidental endwise displacement of the switch rod button from the assembly because these shoulders will strike the side edges of the sloping lever portion 15 and prevent the notch 18 from moving past the sloping lever portion. However, when it is desired to remove the switch assembly, it is only necessary to rotate the rod 62 around its axis sufficiently far to cause either the upper or lower corner 84 of the solid shaft portion to function as a cam and depress the sloping lever portion 15 sufficiently to clear the notch 18. Thereupon, the switch actuating rod can be shifted endwise entirely out of the switch assembly so that the switch assembly can be then withdrawn from the right hand end of the cored opening 56. It will be noted from Figure '7 that the ends of the switch actuating rod 62 have a spherically rounded formation 85, and this facilitates the operation of camming the inclined lever portion 15 downwardly as the switch actuating rod is inserted in place in the operation of assembling the switch unit within the device. The electrical connections between the contact springs 68, 69, electric cord and motor terminals will be obvious.

The above construction and arrangement of switch has advantageous cooperation with my improved transfer tool, particularly because it enables-the motor to'be started and stopped by the fingers of the same hand that is pressing the tool downagainst thetr'ansfer sheet. This leaves the other hand entirely free for holding the transfer sheet; for maneuvering it to different positions overthe drawing or tracing, and for smoothing: out any wrinkles or irregularities in" the surface ofthe transfer sheet or in the surf'aoe of the tracing: For example, if the tool being heldin the right hand, the switch actuating rod button 62- can be thrust to the rightby/the thumb of the right hand for starting'the motor, and the rod button-can be thrust to the left by either of the last two fingers of the-right hand for stopping the motor, all without interrupting the grip of theright hand on the-handle portion [3, and without interrupting the continuous sliding motion of the tool over the transfer sheet. Thus, the left hand remains entirelyfree for gripping the transfer sheet, maneuveringit, pressing it down against the work sheet, smoothing out both sheets, etc. This greatly expedites the use of the tool, enabling it to be operated more rapidly over a greater rea of surface.

While I have illustrated and described what I regard to be the preferred embodiment of my invention, nevertheless it will be understood that such ismerely exemplary and that numerous modifications and rearrangements may be made therein without departing from the essence of the invention.

I- claim:

1. In a motor driven transfer tool for transf-erringmarkings from a transfer sheet to a receiving surface, the combination of a sliding base plate adapted to rest upon and have sliding motion over said'transfer sheet, a handle portion extending upwardly from said base plate, an electric motor mounted above said base plate with its axis extending substantially at right angles thereto, a rubber sleeve coupling having its upper end connected to the shaft of said motor, and arotating pressure head connected to the lower end of said rubber sleeve coupling, said'pressure head comprising a plurality of independently rolling balls adapted to have rolling pressure contact with the transfer sheet, said rubber sleeve coupling yielding in compression when said balls'are brought to bear against said transfer sheet so that said balls will have resilient pressure engagement against the transfer sheet in the operation of the tool;

2. In a motor driven transfer tool for transferring markings from the transfer sheet to a receiving surfacethe combination of a casting comprising a sliding'base. portion adapted to rest upon and have sliding'rnotion over the back side of said transfer'she'et, said base'piate having a horseshoe-shaped opening at one end, said castingc'omprising a handle portion extending upwardly from the other end of said base'plate; nd including a' motor mounting ring disposed above said horseshoe-shapedopening, an electric motor mounted insaid mounting ring with its axis extending vertically, a rubber coupling having its upper end connected with the motor shaft, a rotatingv pressure head connected with the lower end of said'coupling, adjusting shim means at one end of said coupling for adjusting the normal position of said pressure head relatively to said base plate, and a ring of independently rolling ballscarried by said pressure head, said shim means being adjusted to cause said rubber coupling to yield in: compression'whensaid balls are brought to "bear against said transfer sheet 8'? sothat saidballs will-be'yieldingly' held in rotating pressure contact with the transfer sheet as the sliding base plateism'oved" over the sheet.

3. In a motor driven transfer tool for trans ferring markings from the transfer sheet to-a receiving surface, the combination of a main body comprising a non-rotating sliding. base plate and a handle portion extending upwardly therefrom, said handle portion adapted to be held inone: handfor pressing said sliding base plate down against the transfer sheet and for sliding the base plate across the sheet in the transfer operation, an electric motor carried by said main body, a' rotating pressure headdriven r by said electric motor and comprising, rolling balls adapted to have rolling pressure contact with the transfer sheet, resilient means controlling the pressure of engagement of said rolling balls with the transfer sheet, and anelectric switch disposed in said sliding base plate portionbelow said handle portion for controlling saidelectric motor, said switchcomprising a-switch actuating member arranged so as to be operable by the same hand that is holding the handle ortion of said main body.

4. In a motor driven-transfer tool for transferring markings'fromthe transfer sheet to areeeiving surface, the combination of a main body comprising anon-rotating sliding base plate and-a handle portion extending upwardly therefrom, said handle portionbeing adapted to be held in one hand for pressing said-slidingbase plate down against the transfer sheet and forsliding the base plate across the sheetin the transfer operation, an electric motor carriedby said main body, a rotating pressure headdriven by said electric motor and comprising rolling balls adapted to have rolling pressure-contact with the transfer sheet, resilient means enabling said balls to have vertically yielding contact'with the transfer sheet, an electric switch mounted in said sliding base plate of the main body below ing'sliding base plate adapted to rest upon and" have sliding. motion-over said'transfer sheet, an

-ctric motor carriedby said base plate com- .r1' a downwardly extending shaft member, a rotating head; member driven" by said'shaft member, one of said members having an axial bore and theother of said members having a relatively loose guiding fit within said bore, a rubber coupling sleeve engaging said shaft memberand said rotating head member, and a plurality of rolling balls projecting downwardly from the under side'of said rotating head member adapted to have rolling pressure engagement against the transfer sheet, saidbase plate being adaptcd't'o' be given a sliding guided motion by the'opera'-' tor over the surface of said transfer sheet inde= pendently of the rotation of said rotating head member; said rubber coupling sleeve" being slightly compressed when said balls are brought to'bear against the transfer sheet so-tha't' said balls will haveresilient pressure engagement 9 against the transfer sheet in the operation of the tool.

6. In a motor driven transfer tool for transferring markings from a transfer sheet to a receiving surface, the combination of a non-rotating sliding base plate adapted to rest upon and have sliding motion over said transfer sheet, said base plate having an opening therein, an electric motor carried by said base plate having a downwardly extending motor shaft, a rotating pressure head disposed in the opening in said base plate and having a vertical axial bore in its upper end, said motor shaft having a relatively loose guided fit within said bore, a rubber coupling sleeve having its upper end engaging over a portion of said motor shaft and having its lower end engaging over a portion of said pressure head, and a ring of independently rolling balls carried by said rotating pressure head and projecting downwardly from the under side thereof to have rolling pressure engagement against the transfer sheet, said base plate being adapted to be given a sliding guided motion by the operator over the surface of said transfer sheet independently of the rotation of said rotating head member and balls, said rubber coupling sleeve resiliently transmitting all driving torque from said motor shaft to said pressure head, said rubber coupling sleeve being slightly compressed when said balls are brought to bear against said transfer sheet so that said balls will have resilient pressure engagement against the transfer sheet in the operation of the tool.

7. In a motor driven transfer tool for transferring markings from a, transfer sheet to a receiving surface, the combination of a non-rotating sliding base plate adapted to rest upon and have a sliding motion over said transfer sheet, said base plate having an opening therein, an electric motor carried by said base plate with the motor shaft disposed substantially vertically, a resilient coupling secured in torque transmitting relation to the lower end of said motor shaft, a, rotating pressure head secured to the lower end of said resilient coupling and extending down through said opening in said base plate, and a plurality of balls carried by said rotating head adapted to be pressed downwardly in rolling contact against said transfer sheet for performing the transfer operation, said resilient coupling resiliently transmitting all driving torque from said motor shaft to said pressure head.

JOHN R. BOYLE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 845,730 Marshall Feb. 26, 1907 1,839,034 Johnson Dec. 29, 1931 1,862,738 Douglas June 14, 1932 2,102,970 Peterson Dec. 21, 1937 2,252,160 Blood Aug. 12, 1941