US2372397A - Starting and stopping power transmission mechanism - Google Patents

Description

March 27', 1945. A. s. SHEROFF 2,372,397

STARTING AND STOPPING POWER TRANSMISSION MECHANISM Filed Dec. 14, 1945 Patented Mar. 27, 1945 UNITED STATES, PA ENT OFFICE I STARTING AND STOPPING POWER TRANsmssIQN MECHANISM Abraham s. Sherofi, Boston, Mass. Application December 14, 1943, Serial No. 514,193

3 Claims. (01

i The presentv invention pertains generally to starting and stopping power transmission mechanisms for transmitting power to power driven machines, more particularly to starting and stopping, power transmission mechanisms which n can be connected directly to sewing machines for transmitting power to such sewing machines, and most specifically to starting and stopping power transmission; mechanisms directly C011! .nected to, and capableof starting and. stopping instantaneously, such sewing machines.

The principal object of the present invention is to provide a power transmission mechanism for interposition. between a sewing machine and a source of power delivered rotationally, such,

for example, as an electric motor, by the use of" which power transmission mechanism the sewing machine can be set into operation at full speed and can thereafter be halted to a dead stop within a cycle of its operation, i. e., within the formationof a stitch.

Another object of the present inventionisto provide a power transmission-mechanism for interposition' between a sewing machine and a source of powerdelivered rotationally, such, for

example, as an. electric motor, that can be so interposed without reconstructing either the sewing machine or the electric motor.

Another object of the present invention is to provide a powertransmission mechanism for interposition. between a sewing machine and a source of power delivered rotationally, such, for example, as. an electric motor, whose motionl arresting mechanism will. function automatically upon disengagement of its motion establishing mechanism. I.

Another object of the present invention is to provide a power transmission mechanism for interposition between. a sewing machine and a source of power delivered rotationally, such, for

example, as an electric motor, whose motion establishing mechanism and motion arresting mechanism are susceptible of. positive control at all times by the user of the sewing. machine.

Another object of the present invention is to provide a power transmission mechanism for interposition between a sewing machine and a source of power delivered rotationally, such, for example, as an electric motor, whose motion establishing. mechanism and motion arresting mechanism are so susceptible of positive control at all times by the user of the sewing machine that the user of the machine can,"by skillful riding of the treadle, operate the sewing machine at, speeds far below its normal'operat'. I

ing speed, and thus can execute stitching along highly inflected curves and around corners unexecutable at the normal operating speed of the sewing machine.

Another object of the present invention is to provide a power transmission mechanismfor interposition between a sewing machine and a Fig. 1.

In the drawing, I is the sewing machine, shown in part just sufiicient to establish the relationship of the present invention thereunto, 2 is its handwheel, 3' is a connecting member secured I rigidly to, concentrically with, and perpendicular to the plane of, the handwheel 2, connecting the handwheel'z by means of the coupling 4 to the gear'wheel 5, the smaller of the two gear wheels in the housing 6', the gear wheel 5 being mounted upon and keyed to the axle 1 turning in bearings inset into the walls of the housing 6 and restrained agai'nst longitudinal movement by the collars 8, 8, secured thereto. Meshed with the gear wheel 5 is a larger gear wheel 9 mounted upon and keyed to a hollow axle l0 turning in bearings inset into the walls of the housing 6 and restrained against longitudinal movement by the collars H, H' secured thereto and passing throughthe wall of the housing 6' to terminate in the bifurcation effected by the slots l2, I2. Mounted upon and secured to the hollow axle I0 is an outside collar ['3 toserve as one abutment for" an expansive spring. Contained by and movable longitudinally within the hollow axle H3 is an inner axle ['4 upon which is mounted and to which. is secured the collar l5 provided with the tongues f6, f6, received by and movable longitudinally in the slots [2, l2; in the hollow axle H],-

the collar 1,5: being adjustable longitudinally along the inneraxle I4 and securable thereto by the pin I 1'. Upon the inner axle I4 is mountedi also the collar 18 provided with the flange IE) to serve as the other abutment for the expansive spring, the collar l8 being adjustable longitudinally along the inner axle I4 and securable thereto by the pin 20, so that the expansive spring 2I mounted upon and encircling the inner axle I4 can be subjected to varied degrees of constraint between the two abutments I3 and I9. Suitably secured to the housing 6 by the bell crank lever support 23 is the bell crank lever 22 to which is secured the rigid rod 24 connectin it with a treadle (not shown) operable by the user of the sewing machine, the action arm of the bell crank lever 22 being either merely in contact with one end of the inner axle I4 (as shown) or actually tiedto that end of the inner axle I4 by means of a suitable ball and socket joint. Upon the other end of the'inner axle I4 iii is mounted and secured a rotatable member 25, v

herein shown as a wheel but not to be limited in any way to this form of construction, whose functions are to serve as a motion establishing element and a motion arresting element. As shown herein, the rotatable member 25 is provided with friction materials 26, 26, mounted upon the inner surface of the rotatable member 25 near its periphery, the one friction material engageable with the frustro-conical braking surface of the braking member 21 mounted upon the side of the housing 6 concentrically with and perpendicular to the inner axle I4, and the other friction material engageable with the frustroconical clutch surface of the clutch member 28 mounted upon and secured to the axle 29 of the electric motor 30 concentrically with and perpendicular to both the axle 29 of the electric motor 30 and the inner axle' I4. The rotatable member should be of design and construction such as to possess the minimum moment of inertia, and the contacting surfaces of the friction materials should be disposed upon the rotatable member 25 as near to its periphery as is compatible with the realization of the optimum of contacting surfaces of the friction materials, the optimum of contacting surfaces of the friction materials being determined by the maximum of contacting surfaces of the friction materials eng ageablev and disengageable in the minimum of time. I

The operation of the present invention is as follows: the user of the sewing machine inserts the work into the sewing machine, and, by press ing his foot down upon the treadle, actuates the rigid rod 24 secured to the bell crank lever 22 whose action arm then displaces the inner axle I4 longitudinally within the hollow axle .I0 against the pressure exerted by the expansive spring 2I upon its abutments I3 and I9 and communicated to the inner axle I4 until the friction material 26 of the rotatable member 25 comes into frictional engagement with the frustro-co-nical clutch surface of the frustro-conical clutch member 23 mounted concentrically and perpendicularly upon, secured to, and rotatable by, the axle 29 of the electric motor whereupon the rotatable member 25 is instantaneously set into motion, which motion is communicated to the larger gear wheel 9 by means of thecollar I5 secured to the inner axle I4 by the pin H, the tongues I6, I6, of the collar I5 being received by and movable longitudinally in the slots I2, I2, in the hollow axle I0 upon which the larger gear wheel 9 is mounted and to which it is keyed. Since the larger gear wheel 9 is meshed with the smaller gear wheel 5 and since the transmission of power from the smaller gear wheel 5 to the sewing machine I is direct, the transmission of power from the electric motor 30 to the sewing machine I is effected instantaneously. As soon as the user of the sewing machine desires to stop the operation of the sewing machine, the user of the sewing machine releases the treadle, and the expansive spring 2|, which has been the more strongly compressed between the abutments I3 and I9 during the engagement of the frustroconical clutch surface of the frustro-conical clutch member 28 with the friction material 26 upon the rotatable member 25, impels the inner axle I4 longitudinally to disengage the frictional material 26 of the rotatable member 25 from the frustro-conical clutch surface of the frustroconical clutch member 28 and to engage the frictional material 26 of the rotatable member 25 with the frustro-conical braking surface of the frustro-conical braking member 21 mounted upon the side of the housing 6 concentrically with and perpendicular to the inner axle I4, the engagement whereof halts the operation of the sewing machine instantaneously. If, however, the user of the sewing machine desires to operate the sewing machine at speeds somewhat less than the normal operating speed of the sewing machine, in order to execute stitching along highly inflected curve and around corners unexecutable at the normal operating speed of the sewing machine, the user of the sewing machine can do so by riding the treadle, i. e., by jiggling his foot upon I the treadle in a rapid manner so that the friction materials 26, 26, of the rotatable member 25 make intermittent and successively alternative contacts with the frustro-conical clutch surface of the frustro-conical clutch member 28 and the frustro-conical braking surface of the frustroconical braking member 21: with a little practice, the user of the sewing machine can execute stitching at relatively constant speeds varying from zero to the normal operating speed of the sewing machine.

While no small part of the success attendant upon the utilization and functioning of the present invention is due to the inertial effect of the presence of gear wheels in the train of mechanisms and the direct connection of the stopping and starting power transmission mechanism with the power driven machine, what is perhaps the chief factor in the realization of the objects of the present invention is the ensemble of the collar I3 and the flange I9 of the collar I8, both serving as abutments for the expansive spring 2I, and the expansive spring 2|, constrained between these two abutments I3 and I9 and rotatable with the hollow'axle I0, whereby longitudinal movement of the inner axle I4 can be effected in either of two directions during the rotation of the hollow axle I0 without the development of frictional forces in planes perpendicular to the longitudinal axis of the inner axle I4 between the collar I3, the flange I9, and the expansive spring 2 I.

It is obvious that drastic changes may be made in the embodiment of the present invention herein presented without departing from the spirit of the present invention. In particular, the clutch means and the braking means are susceptible of great'alteration within the spirit of the present invention. Hence the present invensource of power delivered rotationally, the combination of a train of gear wheels within a housing, connecting means connecting positively one of thegear wheels with the power driven machine, a hollow axle carrying a second gear wheel secured thereto and provided at one of its ends with bifurcating slots, a collar secured upon the hollow axle, an inneraxle displaceable longitudinally within the hollow axle, a second collar secured upon the inner axle and provided with tongues receivable and displaceable longitudinally in the bifurcating slots of the hollow axle,

a third collar secured upon the inner axle, a rotatable member carried by and secured to the inner axle at its other end, brakin means distributed between the rotatable member and the housing of the gear wheels, and an expansive spring encircling the hollow axle and the inner axle and constrained between the first collar and the third collar for maintaining in engagement the braking means.

2. In a starting and stopping power transmission mechanism interposed between and in combination with a power driven machine and a source of power delivered rotationally, the combination of a train of gear wheels, connecting means connecting positively one of the gear wheels with the power driven machine, a hollow axle carrying a second gear wheel secured thereto and provided at one of its ends with bifurcating slots, a collar secured upon the hollow axle, an inner axle displaceable longitudinally within the hollow axle, a second collar secured upon the inner axle and provided with tongues receivable and displaceable longitudinally in the bifurcating slots of the hollow axle, a third collar secured upon the inner axle, an expansive spring encircling the hollow axle and the inner axle and constrained between the first collar and the third collar, a rotatable member carried by and secured to the inner axle at its other end, clutch means ,distributed between the rotatable member and machine for displacing the inner axle longitudinally to engage the rotatable member with the source of power delivered rotationally.

3. In a starting and'stopping power transmission mechanism interposed between and in combination with a power driven machine and a source of power delivered rotationally, the combination of a train of gear wheels within a housing, connecting means connecting positively one of the gear wheels with the power driven machine, a hollow axle carrying a second gear wheel secured thereto and provided at one of its ends with bifurcating slots, a collar secured upon the hollow axle, an inner axle displaceable longitudinally within the hollow axle, a second collar secured upon the inner axle and provided with tongues receivable nad displaceable longitudinally in the bifurcating slots of the hollow axle,

a third collar secured upon the inner axle, a

spring encircling the hollow axle and the inner axle and constrained between the first collar and the third collar for maintaining the braking means in engagement, and means operable by the user of the power driven machine to engage and disengage the clutch means and the braking means.

ABRAHAM S. SHEROFF.

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