US2846552A

US2846552A - Plural-purpose controller for electric sewing machines and the like

Info

Publication number: US2846552A
Application number: US537860A
Authority: US
Inventors: Winz Karl
Original assignee: GM Pfaff AG
Current assignee: GM Pfaff AG
Priority date: 1954-10-09
Filing date: 1955-09-30
Publication date: 1958-08-05
Anticipated expiration: 1975-08-05

Description

Aug. 5,1958

Filed Sept. 50} 1955 K. WINZ PLUR AL-PURPOSE CONTROLLER FOR ELECTRIC SEWING MACHINES {\ND THE LIKE 2 Sheets-Sheet 1 AfTOAA/EY Aug. 5, 1958 K. wmz 2,846,552

PLURAL-PURPOSE CONTROLLER FOR ELECTRIC SEWING MACHINES AND THE LIKE Filed Sept. 50, 1955 2 Sheets-Sheet 2 IN V EN TOR. A42? M/vz United States Patent PLURAL-PURPOSE CONTROLLER FOR ELECTRIC SEWING MACHINES AND THE LIKE Karl Winz, Kaiserslautern, Germany, assignor to G. M.

Pfalf A. G., Kaiserslantern, Pfalz, Germany, a corporation of Germany Application September 30, 1955, Serial No. 537,860

Claims priority, application Germany October 9, 1954 5 Claims. (Cl. 201--48) The present invention relates to improvements in plural-purpose starters or controllers for electric sewing machines and the like embodying a variable resistance unit and actuating means therefor for continuously varying the motor or operating speed.

It has been customary in the past, especially in the case of electric sewing machines, to construct the controller for either foot, knee or pull control for variation of the motor speed. This has made it necessary to provide and keep in stock a considerable number of units or types of controllers and/ or machines to suit individual customer desire or requirements. This constitutes an undue burden on both the fabrication and sales and marketing operations, not to speak of the added manufacturing and overhead expense involved.

While it has already been proposed to construct a controller unit so that it can be adapted for use in different modes of operation, in particular for either foot or knee control, the prior constructions have not been fully satisfactory both with regard to a quick and instant change from one to the other mode of operation by the average person without the use of special tools or skill, as well as by the lack of simple means for converting and adapting the units instantly and efiiciently from any one to another of the conventional operating modes, that is, foot, knee or pull control, to suit any existing operating condition or requirements.

Accordingly an important object of the present invention is the provision of a plural-purpose starter or controller for electric sewing machines or the like which is both simple in design and construction and which will enable a quick and ready conversion or adaptation from any one to another of the conventional operating modes, that is, by a foot pedal, knee lever or pull control element respectively.

Another object of the invention is the provision of a basic plural-purpose controller unit which will require a minimum of attachment or conversion parts for adapting the unit to any of the various operating modes or controls.

A further object of the invention is the provision of a readily adaptable plural-purpose controller which can be converted from one to another operating mode with a minimum of operations and without the use of special tools or skilled labor.

Still a further object is the provision of adjustable mounting means for a plural-purpose controller of the type referred to, to ensure adequate stability and other conditions of operating safety in the various uses and operating modes of the unit.

The above and further objects, as well as novel aspects of the invention will be better understood from the following detailed description of a practical embodiment taken in reference to the accompanying drawings, forming part of this specification and in which:

Fig. 1 is a perspective bottom view of the basic construction unit of a plural-purpose controller embodying 2,346,552 Patented Aug. 5, 1558 the principles of the invention, the bottom wall of the unit being removed to reveal the inside construction;

Fig. 2 is a partial view of Fig. 1 with the bent lever removed and its pivot shaft shown separately in exploded view;

Fig. 3 is a partial perspective view of the angular control lever for eifecting foot-controlled operation of the controller;

Fig. 4 is a schematic side View of the assembled controller shown on a reduced scale and adapted for foot operation;

Fig. 5 is a perspective view showing the controller adapted for knee lever control and mounted in vertical position on the inside of the sewing machine cabinet or the like;

Figs. 5A and 5B are separate plan views, respectively, of the bent actuating lever and extension member therefor for knee lever control;

Fig. 6 is a perspective top view of the basic controller unit with the bent actuating lever removed to reveal the auxiliary control shaft used for pull control;

Fig. 6A shows the auxiliary actuating lever and fastening screw therefor, provided for pull control of the unit;

Fig. 7 is a further perspective view of the basic controller unit according to the invention shown mounted upon the cabinet wall of a sewing machine or the like for pull-controlled operation; and

Fig. 8 is a perspective bottom view of the controller unit showing an improved feature for supporting and mounting the units for use in its various operating modes.

Like reference numerals identify like parts throughout the different views of the drawings.

Referring more particularly to Figs. 1 to 3, the reference numeral 1e indicates an oblong flat housing of any suitable material (metal, plastic, etc.) preferably provided with a slanting top, Fig. 4, and being fitted at one of its short ends with a current supply base or socket 11 for connecting the controller to an electric power line or network. Mounted within the casing 10 is a variable electrical resistance unit 12, preferably, though not limitatively, of the type comprising a stack or pile of compressible carbon elements, such as discs or plates, to provide a stepless or continuously variable resistance proportional to a compressive control force applied to the stack. The resistance 12 serves in a known manner to vary the operating current or voltage of the driving motor of a sewing machine or the like, to correspondingly vary the motor speed. In case of a sewing or similar machine, with the load subject to substantial fluctuations, the motor is advantageously of the series wound type with the controller resistance connected in series with the motor winding, to enable an effective speed control under varying load conditions, in a manner well known to those skilled in the art.

The special construction of the resistance unit 12 provided with suitable terminal means 13 is immaterial for the present invention, the latter relating to improved operating mechanism or instrumentalities to enable a plural control and operation. There is provided for this purpose an actuating rod 15 extending through or otherwise guided by the insulating casing of the unit 12, a coil spring or the like being interposed between one of the projecting ends of said rod and the compressible resistance (see also Fig. 4), whereby a pull exerted upon the opposite end of the rod 15 results in a varying stack pressure upon the carbon elements and, in turn, a corresponding variation of the electrical resistance of the unit.

In order to operate the controller in the various modes or manners pointed out, there is provided according to the invention an intermediate actuating member 14 of a suitable insulating material and secured to the projecting end of the rod on the side opposite to the control or balance spring 16. Connecting member 14 may be operated along a predetermined substantially linear path by either one of two control means in order to adapt the controller for foo-t control, knee control, or pull operation, to suit existing conditions or requirements. More specifically, for effecting foot or knee operation of the controller, there is provided a bent actuating lever 17, Fig. 3, having a short lever arm in the form of two parallel elements or prongs 18 and a relatively longer lever arm serving as a foot pedal 28, Fig. 4. Lever 17 is removably supported by a transverse pivot shaft 19 secured to the housing 10 in any suitable manner, such as by means of a pair of depending perforated ears or supports 21 formed by inwardly bending portions of the housing top wall, the shaft 19 being passed through a hole or here 22 in one of the side Walls of the housing and having a threaded end 23 engaging the internally threaded bore of one of the supports 21 to firmly and removably secure the shaft in place. Alternatively, shaft 19 may be secured to or supported in suitable bores of the opposite side walls of the housing, to dispense with the separate supports 21.

The bent actuating lever 17 is pivoted upon the shaft 19, the latter passing through holes 24 in the lever arms 18, operative connection of the latter with the member 14 being effected by the cut-out ends 25 of the arms 18 engaging the projecting ends of a rod or shaft 26 secured in the member 14. The arms 18 of the bent lever are passed through an opening 27 in the top wall of the housing 10 such that the pedal or arm 20 of the lever extends above and along the housing 10, as more clearly shown in Figs. 4 and 5 of the drawings. The end of the arm 2t carries a removable roller 28 to provide a pedal for easy and convenient foot operation of the controller. With this construction and operation the foot of the operator produces a further mechanical advantage by acting as a cantilever with the heel 30 providing a fixed pivot point and the sole 31 engaging the roller 28 and acting as a lever arm, in the manner shown in Fig. 4. The construction of the lever or foot pedal and operating has the result of a reduced stroke or minimum deflecting angle required to cover the full range of the resistance variation or speed control, resulting, in turn, in greater convenience of operation and reduced fatigue on the part of the operator over prolonged operating periods.

If the controller is to be used for knee lever operation, the roller 28 of the arm or actuating member 20 is removed, such as by unscrewing the shaft 32 of the roller, Figs. 5 and 5A, removing the roller and replacing it by an extension member or knee lever 33, Figs. 5 and 5B, removably held by the arm 20 in any suitable manner, such as by means of an extending angularly or reversely bent tongue 34 engaging the end of arm 20. In this case the controller in advantageously mounted in a vertical position on the inside of the cabinet of a sewing machine or the like, as shown in Pig. 5.

There are further provided according to the invention exchangeable means or instrumentalities for adapting the unit to pull control or operation. For this purpose a further auxiliary lever arm 35 has one end pivotally connected to the intermediate member 14 and has its opposite end secured to a shaft 36 being at right angle to the shaft 19, in the example illustrated, and journaled in the bottom and top walls of the housing, shaft 36 extending slightly above the housing top and being concealed by the member 28 in the foot or knee operated position of the unit. The extendnig end of shaft 36 has a square shape, as shown at 37, Fig. 6, for removably connecting to it a further auxiliary operating lever 38 parallel to and overlying the top wall of the housing, as shown in Figs. 6A and 7. For this purpose, lever 38 has a square opening at one end fitting the end 37 of shaft 36 and being secured in place by a screw 40 or in any other Suitable manner. As a result, the assembly comprising the arm 35, shaft 36 and arm 38 provides an additional actuating means of the resistance 12 controlled by applying a downward pull to the free end of the lever arm. The latter may be provided with a further fastening screw 41 or the like for attaching a suitable pulling member, such as a cord or rod 42, as shown in the drawing.

According to a further feature of the invention, a plural-purpose controller of the type described is fitted with means to insure both high mechanical stability and other safety conditions in the various operating modes or positions of the unit. For the latter purpose, the controller housing 10 is fitted, as shown in Fig. 8, with supports or feet 45 of rubber or an equivalent material and adjustably secured to the base or bottom wall of the housing, in such a manner as to be located either within the confines of the housing to serve as supports providing adequate mechanical stability of the unit in the footoperated position, Fig. 4, or to extend beyond the edges of the housing to serve as means for mounting the controller upon a cabinet wall or the like, for pull or knee control, as shown in Fig. 5. In the latter case, the feet 45, if made of rubber or an equivalent material, act as heat insulators or separators, preventing excessive heating of and damage to the cabinet, especially a Wooden cabinet, whreby to dispense with the need of any separa-e heat insulation.

For this purpose, four perforated feet 45, as shown in Fig. 8, having mounted therein suitable eyelets or hollow rivets 46, are each secured to one end of the slotted adjusting plates or slides 47 which are secured to the underside or bottom wall 48 of the housing 10 by set screws 50 passing through the slots 51 of the slides 49 and engaging corresponding tapped holes in the wall 48. As a result, the feet 45 may be adjusted in any desired position by loosening and re-tightening the screws 50. Thus, for foot operation of the controller, the feet may be located within the confines of the housing 10, as shown for the upper left hand foot and the lower right hand foot in the drawing. This will insure optimum mechanical stability of the controller for use in this mode of operation, as shown in Fig. 4. For mounting the controller in a vertical or other position upon a cabinet wall or the like, for knee lever or pull control, the feet 45 are extended beyond the bottom wall of the housing 10, as shown for the lower left hand foot and the upper right hand foot in Fig. 8. As is understood, the adjusting angle of the feet or slides 47 may be either normal to the edges of the housing, as indicated by the arrows in the drawing, or at any other angle by rotating the slides to a desired position prior to the tightening of the screws 50, to suit existing conditions and mounting requirements. Mounting of the controller may then be simply effected by means of screws or bolts passing through the holes in the rivets or eyelets 46. Thus, Fig. 5 shows the unit mounted upon the vertical inside wall of a sewing machine cabinet with the feet 45 extended at right angle to the housing and acting both as resilient supports and heat insulators, in the manner pointed out and readily understood from the foregoing.

In the foregoing the invention has been described with reference to a specific illustrative device. It will be evident. however. that changes and modifications. as well as the substitution of equivalent parts and elements for those shown, may be made without departing from the broader scope and spirit of the invention as set forth in the appended claims. The specification and drawings are accordingly to be regarded in an illustrative rather than in a limiting sense.

I claim:

1. In a controller for electric sewing and the like machines comprising a fiat casing having top and bottom walls, electrical resistance means within said casing, an intermediate control member connected to said resistance means being normally resiliently urged to a position of maximum resistance and operable over a predetermined path in a direction substantially parallel to said casing walls, to vary the resistance between maximum and minimum, and vice versa, for controlling the operating speed of said machine, a first angular control lever having a first lever arm extending substantially transversely to said casing walls and having one end engaging said member, means removably and pivotally mounting said lever arm upon said casing with the opposite end thereof protruding beyond the top Wall of said casing, a second lever arm of said control lever forming an angle with said first lever arm and extending alongside and in spaced relation to said top wall, whereby to allow control of said member by foot pressure applied to the free end of said second lever arm in the horizontal op erating position of the controller, and a second control lever having a first lever arm movable in a plane substantially parallel to said casing walls, said last lever arm secured to said member and pivotally mounted upon said casing, a second lever arm removably connectible to said first lever arm of said second control lever, for controlling said member independently of said first control lever, thereby to allow of control of said resistance means with said casing arranged in vertical mounting position by a vertical pulling force applied to said second lever arm of said second control lever.

2. A controller as claimed in claim 1, including a removable roller mounted upon the free end of said second lever arm of said first control lever, and an auxiliary knee-operated lever arm removably connectible to said free end upon removal of said roller, for effecting knee-operated control of said resistance means in the vertical mounting position of the controller.

3. A controller as claimed in claim 1, wherein said second lever arm of said second control lever is removably connectible and extends beyond and in the direction of the top Wall of said casing.

4. A controller as claimed in claim 1, including a plurality of supporting feet upon the bottom wall of said casing, and means for adjusting said feet to extend beyond the confine of said casing, thereby to serve, respectively, as supporting means in the horizontal operating position and as mounting means in the vertical operating position of the controller.

5. A controller as claimed in claim 1, including a plurality of perforate supporting feet upon the bottom wall of said casing consisting of resilient and heat resistant material and fitted with metal eyelets, and means for adjusting said feet to extend beyond the confine of said casing, to serve, respectively, as supporting means in the horizontal operating position and as mounting means in the vertical operating position of the controller.

References Cited in the file of this patent UNITED STATES PATENTS 1,772,361 Mross Aug. 5, 1930 2,181,543 Bentz Nov. 28, 1939 2,193,964 Hastings Mar. 19, 1940 2,557,259 Chason June 19, 1951 2,561,556 Bell July 24, 1951 FOREIGN PATENTS 594,933 Germany Mar. 15, 1934 1,016,591 France Aug. 27, 1952