US 3340835 A
Description (OCR text may contain errors)
Se t. 12, 1967 A. COOK ETAL SEWING MACHINE MOTQR MOUNTS 2 Sheets-Sheet l Filed Oct.
INVENTORS A be f N. Cook and By Ronald R. Thompson.-
. I ATTORNEY Sept. 6 A. N. COOK ETAL SEWING MACHINE MOTCR MOUNTS 2 Sheets-Sheet Filed w.
v INVENTORS Albert N.Cook and Ronald R. Thompson.
ATTORNEY WITNESS W530i United States Patent 3,340,835 SEWING MACHINE MOTOR MOUNTS Albert N. Cook, Madison, and Ronald R. Thompson, Pluckemin, NJ., assignors to The Singer Company, New York, N.Y., a corporation of New Jersey Filed Oct. 1, 1965, Ser. No. 492,253 4 Claims. (Cl. 112-220) This invention relates to means for adjustably and removably mounting an electric motor for gear drive within the frame of a sewing machine and more especially relates to structural features thereof which provide ease of assembly productive not only of a resilient mounting but also of a stable and proper gear mesh.
The modern high-quality family sewing machine today invariably uses a built-in electric motor with a gear drive. With the constant demand for an ever increasing variety of stitch types, the internal mechanism has now become quite complex and the space available for manipulation and mounting of the motor during assembly has accordingly been reduced.
It becomes important therefore to devise an effective motor mount which shall be simple in assembly, use a minimum number of parts and preferably requires only a single easily accessible securement for proper installation in a sewing machine for driving same through a gear transmission. It is especially important, that such a motor mount provide simple means for inherently securing and maintaining a proper gear mesh so that the maximum motor torque is available for driving the sewing mechanisms.
The above requirements are satisfied by structure according to this invention, which structure provides limited torsional resilience about the motor shaft axis for noise reduction but maintains rigid alignment for proper gear mesh and accommodates nominal variations in motor length, requiring but a single easily accessible fastening element.
It is an object of this invention, therefore, to provide simple means for resiliently mounting an electric motor with a gear drive within the frame of a sewing machine with special means for inherently securing and maintaining proper gear mesh.
It is a further object of this invention to provide means for adjustably securing an electric driving motor within the frame of a sewing machine, which mount requires the use of a single easily accessible fastening element.
Other objects of this invention will readily be apparent when the following description is considered in connection with the accompanying drawings:
In the drawings:
FIG. 1 is a perspective view of a sewing machine frame showing the general arrangement of the motor mount with respect thereto.
FIG. 2 is a side elevational view, partly in section, taken through the frame of FIG. 1 showing an embodiment of the motor mount of this invention.
FIG. 3 is an exploded perspective view of the parts of the motor mount of FIG. 2.
FIG. 4 is a detailed sectional view taken substantially on the line 4-4 of FIG. 2.
An embodiment of the motor mount of this invention is applied Within the stylized frame of a sewing machine as shown generally in FIG. 1. The frame 10 forms the subject matter of a copending United States patent application Ser. No. 463,677, filed June 14, 1965 and assigned to the same assignee as the present invention. Reference to the above may be had for a full understanding of the construction of frame 10.
-It is sufficient for the purposes of the present invention to note that the upright arm portion 11 of frame 10 includes a vertical front wall 12, a. vertical rear wall 13, and a horizontal platform 14, all being cast integrally.
An electric driving motor 15 having housings 21 and 23 is mounted in an inclined position within the upright arm portion 11 between the front and rear walls 12 and 13 as best seen in FIG. 2. A worm 16 secured to shaft 17 of the motor 15 extends through a rearwardly inclined and apertured portion 18 of the horizontal platform 14 to drivingly engage a gear 19 fixed to an armshaft 20 which drives the sewing mechanism (not shown). This inclined position permits close coupling between the motor 15 and the gear 19 and simplifies the motor construction by eliminating the need for a long shaft extension between the armature of motor 15 and the worm gear 16. This close coupling also maintains better alignment for proper gear mesh.
The housing 21 of motor 15 is formed with a smooth cylindrical hub 22 of reduced diameter. The housing 23 is also formed with a cylindrical hub 24 of reduced diameter. The cylindrical hub 24, however, is interrupted by peripherally-spaced grooves 31 aligned with the shaft axis. The cylindrical hubs 22 and 24 are made coaxial with the bearing-receiving bores in their respective housings 21, and 23, so that, when assembled, the motor 15 presents two axially-spaced cylindrical hubs coaxial with the shaft axis.
A flanged bushing 25 made of resilient material is seated on the cylindrical hub 22 and is received in a smooth cylindrical bore 26 made in the inclined portion 18 of the horizontal platform 14. The flange 28 of bushing 25 lies between the housing 21 and the inclined portion 18 to provide a nominal axial spacing which is in no sense critical with respect to proper meshing of gears 16 and 19. The bushing 25 fits snugly within the bore 26 and is a push fit on the cylindrical hub 22 for ease of assembly but this structure of itself will not frictionally support the full torque reaction necessary to drive the arm-shaft 20.
A flanged bushing 29 of resilient material is seated on the cylindrical hub 24 and is formed with inwardly extending axial ribs 30 which mate with the grooves 31 in the hub 24. Outwardly extending axial ribs 32 are formed on the bushing 29.
The vertical front wall 12 is formed with a boss 33 having an open semi-cylindrical seat 34 formed therein by counter boring with respect to the bore 26 during machining of the casting. The seat 34 thus formed is coaxial with the bore 26 and with an imaginary axis, which upon assembly, coincides with the motor shaft axis.
A removable clamp bracket 35 as best seen in FIG. 3 is formed with a cylindrical bore 36 having outwardly extending grooves 37 which mate with and receive the axial ribs 32 on the bushing 29. The bracket 35 also has an outer portion 38 of extended axial dimension and providing a semi-cylindrical peripheral surface 39 which is coaxial with the bore 36 and receivable on seat 34. A headed screw 40 passes through a slot 41 made in the outer portion 38 and is threaded into the boss 33 for clamping the bracket 35 to the boss 33 when properly seated. The slot 41 provides limited adjustment of the bracket in a direction along the motor shaft axis. A depending finger-piece 42 facilitates the handling of the bracket 35 during assembly.
It will be understood that the ribs 30 and 32 formed on the bushing 29 cooperate with the grooves 31 and 37 formed respectively in the hub 24 and the bracket 35 to form a resilient connection between the motor 15 and the stationary bracket 35, which connection has limited torsional resilience 'but is capable of supporting the full driving torque of the motor by shear stress set up in bushing 29. v
The fact that the bushing 25 is rotatable on the hub 22 and in the bore 26 provides easy manipulation of the motor for aligning the ribs 32 in the grooves 37. That is to say there is substantially no resistance at the gear end of the mount to turning of the motor bodily about the shaft axis necessary to align ribs 32 in grooves 37 and at the same time to seat surface 39 properly on the seat 34 inherently to fix the alignment of the shaft axis with respect to the pitch line of gear 19.
When this has been done, the bracket 35 is pushed along the shaft axis as permitted by the slot 41 and screw 40 and with surface 39 of bracket 35 firmly against seat 34 until all axial motion is taken up and the bushings 25 and 29 are fully seated on the respective hubs 22 and 24 and within the respective bores 26 and 36. It will be seen that, with this construction, motors having nominal variations in length due to manufacturing tolerances can easily be accommodated without adversely affecting the proper gear mesh which is fixed inherently by the seating of surfaces 39 and 34 as above explained.
The fact that the bushings 25 and 29, in their confined states in this assembly,-do not yield substantially in compression means that the proper alignment for gear mesh, when once secured, will be maintained indefinitely, the torsional resilience merely permitting a slight rotation of the motor about the shaft axis, which rotation does not adversely affect the gear mesh but does provide desirable isolation of motor noise.
With the bracket 35 removed, it is evident that the motor 15, with bushing 25 in place on hub 22 and bushing 29 in place on hub 24, can be installed from below with the shaft end projecting through the apertured portion 18 and the bushing 25 seated in bore 26. Then the bracket 35 is applied to seat 34, the motor rotated bodily to align ribs 32 with grooves 37 after which the bracket 35 is pushed into firm engagement With bushing 29 seated in bore 36 and the screw 40 is finally tightened to lock the entire assembly.
Having thus described the nature of the invention, what is claimed herein is:
1. Apparatus for removably supporting an electric motor within the frame casting of a sewing machine having a vertical front wall, a vertical rear wall and a horizontal platform therebetween comprising a rearwardly and downwardly inclined portion of said horizontal platfor joining said rear wall and having a cylindrical aperture formed therein, a rearwardly and upwardly inclined portion of said front wall extending normally toward said downwardly inclined portion and having an open semicylindrical seat formed therein coaxially with said cylindrical aperture, a first flanged resilient bushing received in said cylindrical aperture, a bracket having an inner cylindrical aperture and an outer peripheral portion formed coaxially with said inner cylindrical aperture, said outer peripheral portion being received on said open semi-cylindrical seat, means removably securing said barcket on said seat, and a second flanged resilient bushing received in said inner cylindrical aperture, said first and second resilient bushings adapted to seat cylindrical end hubs of a motor shaft.
2. Apparatus according to claim 1 wherein the means removably securing said bracket on said seat includes slot and screw means providing translational positioning of the bracket relative to the seat.
3. Apparatus according to claim 1 wherein said second flanged bushing includes circumferentially-spaced radial portions and said inner cylindrical aperture of said bracket includes mating portions interengaging said circumferentially-spaced radial portion to support the driving torque reaction between the motor and the bracket.
4. Apparatus according to claim 3 wherein said circumferentially-spaced radial portions and said mating portions of said bracket are ribs and grooves, respectively.
References Cited UNITED STATES PATENTS 2,617,375 11/1952 Peets 112--220 v FOREIGN PATENTS 636,409 1/ 1928 France.
JORDAN FRANKLIN, Primary Examiner.
G. H. KRIZMANICH, Assistant Examiner.