Abstract:
This disclosure relates to an electromagnetic selector system for selecting pattern cams in a sewing machine wherein operator influenced electric pattern selection switches are provided with each said switch corresponding to a pattern on a pattern cam. An adder mechanism is responsive to switch selection for positioning a pattern cam follower in order to transmit the pattern information from the pattern cam to the appropriate sewing instrumentality for reproducing the selected pattern.

Description:
BACKGROUND OF THE INVENTION 
     It is known in the sewing machine art to provide a plurality of pattern cams having pattern information thereon in order to reproduce ornamental stitching in a fabric. Such pattern cams are generally read by mechanical cam followers which are selected individually by relatively complicated mechanical mechanisms for transmitting the pattern information from the pattern cam to the various sewing instrumentalities. Other mechanisms have recently become known in the prior art for providing ornamental stitching such as the adder type mechanism shown in U.S. Pat. No. 3,812,729 and the electronic memory-type system as illustrated in U.S. Pat. No. 3,872,808. There have also been other proposals for providing means to electromagnetically select individual pattern cams in accordance with a manually operable switch means such as illustrated in U.S. Pat. No. 3,874,312. The prior art cited in the latter mentioned U.S. patent also shows that it has been known in the art to provide electromagnetic means for cam selection of various types. In accordance with the present invention an electromagnetic cam selection means is provided wherein movement of a cam follower is initiated to a cam selection position by an adder mechanism which in turn is activated by an operator influenced manually operated electric switch means. The switch means is also operative for selecting a pattern from a pattern cam corresponding to the pattern selected by the switch means. The present invention has one advantage in that it may be incorporated into known type mechanical pattern cam machines having a single follower by adding the mechanism of the present invention, as will be understood hereinafter, without completely requiring a major conversion of the pattern mechanism of the machine. Further, as will also be apparent hereinafter, the adder mechanism of the machine is really simple in construction having relatively few moving parts which move only during pattern selection thereby eliminating the problems of wearing of parts and noise which was present in some of the prior art type adder mechanisms. 
     SUMMARY OF THE INVENTION 
     In accordance with the preferred embodiment of the present invention, a cam stack having a plurality of pattern cams is provided along with a single cam follower for reading the patterns from the pattern cams in a similar manner to that which is known in prior pattern cam sewing machines. In order to select a desired pattern cam, a binary adder mechanism is provided which comprises a plurality of pairs of relatively movable substantially wedge-shaped elements, movement of one of the movable elements of which being initiated by solenoid mechanisms associated therewith. The solenoid mechanisms are operatively associated with switch means for selecting appropriate initiation of movement of one or more pairs of binary adder elements to move the pattern follower to an appropriate pattern cam which corresponds to the pattern selected by the switch means. An override cam and follower are also provided and which are operative for only a short period of time and which are adapted for facilitating the relatively rapid movement of the pattern cam followers into engagement with the appropriate pattern cam. 
     Accordingly, it is one object of the invention to provide a novel and improved electromagnetic pattern cam selecting mechanism for a sewing machine. 
     It is a further object of the invention to provide a novel and improved electromagnetic cam selector mechanism for a sewing machine including a binary adder mechanism for initiating appropriate movement of the pattern cam follower in relation to the pattern cam elements. 
     It is an additional object of the invention to provide a novel and improved pattern cam selecting mechanism for a sewing machine wherein in response to selection of an electric switch a pattern cam will be selected for reproducing an ornamental pattern corresponding to the electric switch selection. 
     Other objects and advantages of the invention will be best understood when reading the following detailed description of a preferred embodiment of the invention with the accompanying drawings in which: 
    
    
     DESCRIPTION OF DRAWINGS 
     FIG. 1 is a perspective view of a sewing machine with portions of the frame illustrated in phantom lines and illustrating the invention as applied thereto, 
     FIG. 2 is an enlarged view of the adder mechanism of the invention, 
     FIG. 2a is an enlarged view of the adder mechanism shown in one operative position, 
     FIG. 3 is a chart illustrating the various combinations of selections which may be made from the binary adder mechanism, and 
     FIG. 4 is a circuit diagram showing an electrical arrangement suitable for operating the pattern cam selection mechanism of the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to FIG. 1, the invention is illustrated therein as being incorporated into the pattern cam mechanism of a sewing machine for influencing the lateral jogging motion of the needle in producing zig-zag or other ornamental stitching. It will be understood however that the invention could be applied to other sewing instrumentalities of the invention such as the feed or other fabric moving type mechanisms. As illustrated, the sewing machine includes a frame 10 having a bed 12 from which rises a standard 14 supporting a bracket arm 16 overhanging the bed. An arm shaft 18 is journalled in the bracket arm and carries a crank 20 connected by suitable linkage to needle bar 22 for imparting endwise reciprocatory movement to said needle bar. The needle bar 22 is provided with a thread carrying needle 24 affixed to its terminal end thereof. The needle bar 22 is slidably supported in a gate 26 which may oscillate on a pivot pin 28 carried on the bracket arm so that lateral jogging movement may be imparted to the needle. A spring 30 serves to bias the gate 26 in a clockwise direction as viewed in FIG. 1 and the lateral position of the gate in opposition to the spring is influenced by a drive link 32 secured to bracket 33 which is pivoted to the gate as at 34. The drive link 32 carries a pivot pin 36 at its other extremity which is accommodated in a radial slot 38 formed in a rock arm 40 which is fixed to rock shaft 42 journalled in the bracket arm 13. The rock shaft 42 also has fixed thereon a wobble plate 44. 
     A dial 46 is provided in bracket arm for adjusting the amplitude of the jogging of the needle bar or the bight and is pivoted about a pivot pin as illustrated. The adjusting dial 46 includes a radial slot 48 embracing a pin 50 extending from a connecting slide 52 which is slidably constrained in a guide slot 54 in the bracket arm and carries a pin 56 accommodated in a slot 58 formed lengthwise in the drive link 32. By this arrangement, adjustment or turning of the dial 46 serves to shift the pivot pin 36 on the drive link 32 along the slot 38 to control the width of zig-zag movements imparted to the needle bar. 
     A cam shaft 60 is journalled in the bracket arm and carries a worm gear 62 drivingly engaging a worm 64 on the arm shaft. A plurality of pattern cams 66a, b, c, d, e, f and g are carried in stacked relationship on the cam shaft as well as a special cam 68 whose function will be described in greater detail hereinafter. As is known in the art, each of the pattern cams 66a - g is provided with an individual cam track thereon which represents an individual ornamental pattern. In order to transmit the pattern informtion from the pattern cam into ornamental stitching, a pattern cam follower 70, which is connected to the wobble plate 44 by means of a spring clip 71 but in sliding relationship therewith, is provided for reading the information from the pattern cam and transmitting it to the wobble plate 44. Vary briefly, as motion is transmitted from the pattern cam through the pattern cam follower 70 to the wobble plate 44, the wobble plate is caused to rock along with its shaft 42 to which it is fixed thus causing the rock arm 40 to swing carrying with it the drive link 32 for initiating jogging movement of the needle bar gate 26 in accordance with the degree of movement initiated by the cam follower 70. 
     In order to initiate movement of the pattern cam follower 70 relative to the individual pattern cams 66a - g for selection of one of said cams, an adder mechanism is provided which is operative in association with an electric switch means influenced by the operator, as will be more fully described hereinafter. Referring again to FIG. 1, it will be seen that the cam follower 70 is supported on a shaft 72 which shaft 72 is suitably supported in the bracket arm 16. The cam follower 70 is mounted on the shaft 72 so that it is rotatable relative thereto and is capable of movement in a linear direction relative to the axis of the shaft 72. Also supported on shaft 72 for linear movement relative to the axis thereof are a plurality of movable adder elements 74a, b and c which as illustrated in FIGS. 2 and 2a have a substantially wedge-shape configuration including a cam surface 78. Supported intermediate each of the adders 74a - c are movable adder elements 76a, b and c, each of which is supported on an associated link member 80a, b and c for movement perpendicular to the axis of the adder shaft 72 for selective operative engagement with the adders 74a - c. As also will be seen in FIGS. 2 and 2a each of the adders 76a - c has a cam surface 82 which is disposed for camming engagement with the cam surface 78 on the adders 74a - c. Each of the link members 80a - c carries a pin 84 for disposition in a slot 86 in each of the adders 76a - c as shown in FIG. 1, so that movement toward and away from the axis of the adder shaft 72 may be initiated by the links 80a - c while permitting movement of the slider adders in a direction along the axis of the shaft 72 relative to the link members due to the length of the slots 86 on said link members 80a - c. 
     Each of the link members 80a - c is formed of a relatively rigid material and is connected at its opposite end to associated solenoids 88a, b and c. The solenoids 88a - c are operative so that when each is turned on its plunger will be drawn inwardly toward the body of the solenoid to move its associated link members 80a - c in a direction toward the shaft 72 thus carrying its associated adder members 76a - c into camming engagement with its associated adder members 74a - c. Spring members 90a, b and c are connected to each link members 80a - c and to a bracket member 91 suitably fixed to the frame for returning the link members to their inoperative position when the associated solenoid is turned off. 
     Further with reference to FIGS. 1 and 4, a plurality of manually operable electric switches, there being seven illustrated in FIG. 1, are supported in the standard 14 and as illustrated in FIG. 4 are connected to the solenoids 88a - c. The switches 92a, b, c, d, e, f and g each represent a separate and individual ornamental pattern which can be selected by the pattern selection mechanism. When an individual switch is selected and depressed by the operator, a particular solenoid or combination of solenoids will be actuated for initiating movement of their associated adders 76a - c into camming engagement with the adders 74a - c associated therewith for initiating linear movement in a vertical direction along the axis of the shaft 72 of said adder 74a - c. As will be apparent, such linear movement of the adders will initiate movement of the cam follower to a distance corresponding to the linear movement of one or more of the linear adders 74a - c. As will be apparent hereinafter, this movement is predetermined so that the cam follower will be positioned adjacent a pattern cam 66a - g which corresponds to the pattern represented by the switch selected by the operator. The predetermined motion of the adder mechanism for initiating movement of the cam follower will be described in greater detail below. 
     As briefly described above, an override cam an adder mechanism is provided in order to permit transition of the pattern cam follower 70 from one pattern to another with relatively rapid movement regardless of the ornamental pattern selected. In order to carry out this purpose, an override or special cam 68 is provided on the cam stack but is spaced above the pattern cams 66a - g. As seen in FIG. 1, the override cam is formed with alternate high cam lobes which are higher than any of the cam lobes of the pattern cams and with alternate low cam stations which are lower than any of the lowest cam stations of the pattern cams. An override or special cam follower 96 is supported on adder shaft 72 for movement along the axis of the shaft and for pivotal movement relative thereto much in the same manner as pattern cam follower 70 and has associated therewith an override adder mechanism comprising an adder element 98 and an adder element 100 which move in much the same manner as the adder mechanism for selecting patterns as described above. The adder element 100 is connected to a link member 102 by a pin 104 disposed in a slot 106 which link member 102 is connected to a solenoid 108 and is spring biased away from the solenoid 108 by a spring 110. The override adder functions in much the same manner as the pattern adder mechanism. 
     The purpose and function of the override adder mechanism is carried out by initiating operation of the override adder each time a pattern is selected. When the override adder mechanism is in operation, the adder 100 will be moved into camming engagement with the adder 98 to raise the follower 96 and the follower 96 will wait until the override cam is rotated to a position wherein a low station is adjacent the follower so that the follower 96 may move into position in the low station and will then ride up onto one of the high stations of the cam 68. As further seen in FIG. 1, the override cam follower 96 is attached to the wobble plate 44 by means of a spring clip 112 but also in sliding relationship therewith. By this means when the follower reaches the high point on the cam 68 the wobble plate will be rocked to an extreme position carrying with it the pattern cam follower 70 which will then be moved away from the pattern cams 66a - g so that it may move in a linear direction parallel to the cam shaft axis in response to the adder mechanism to a position adjacent the associated selected pattern cam. 
     As mentioned above, the pattern cam follower 70 is attached to the wobble plate 44 by means of a spring clip 71 so that its movement will follow the movement of the wobble plate 44 initiated by the override follower 96. In that the high cam point of the override cam is higher than any high point on the pattern cams the pattern cam follower 70 will be moved completely out of the path of any of the high points on the pattern cams so that it will be free to move in its linear path to its selected pattern cam position as mentioned above. 
     With further reference to FIG. 1 it will be seen that a switch mechansim 114 is provided adjacent the wobble plate 44 and is positioned so that it will be actuated when the wobble plate is in one extreme position of its movement. This extreme position is reached whenever the override follower 96 is at the maximum high point on the override cam 68. When the wobble plate 44 reaches its extreme position it actuates the switch 114 which in turn shuts off the solenoid 108 controlling the adder 100 and the spring 110 will then cause the adder to withdraw thereby permitting the override cam follower to drop out of camming engagement with the override cam 68. The effect of the override adder mechanism therefore is to enable positioning of the pattern cam follower 70 relative to the pattern cams 66a - g. The operation of the override mechanism is only momentary and after serving its function is turned off so that it no longer has any effect on the mechanism until a new pattern is selected whereupon the override mechanism will again be activated. Thus it will be seen that the override mechanism is energized for only a short period of time relative to the stitching cycle. 
     The relationship of the pattern adder mechanism and the override adder mechanism collectively called the adder mechanism is a binary one with each pair of adder elements being constructed for initiating movement of the associated cam followers a discrete amount different from each other pair of adder elements. Referring to FIG. 3 a binary selection chart is illustrated therein which lists the distance of follower movement according to the adder selection. For example, it will be seen that if switch 92a is depressed solenoid number 108, which is the override solenoid will be the only solenoid activated. In that none of the pattern adders are activated the pattern cam follower 70 will not move along the shaft 72 and it will remain in its lowermost position with reference to FIG. 1 adjacent the pattern cam 66a. Thus when the solenoid 108 is shut off due to the extreme movement of the wobble plate 44 to close the switch 114 the cam follower 70 will be disposed in operative engagement with the pattern cam 66a so that that particular ornamental pattern will be reproduced during machine operation. As a further example, if switch 92e is depressed solenoids 88a, 88c and 108 will be activated for initiating movement of the pattern cam follower 70 along the adder shaft a distance of 0.500 inches to place the pattern cam follower 70 adjacent patterm cam 66e. The arrangement and construction of the adder mechanism is such that, in the preferred embodiment, actuation of solenoid 88a for initiating movement of adder element 76a into engagement with adder element 74a will cause total movement of the pattern cam follower of 0.125 inches, actuation of solenoid 88b for initiation of movement of adder 76b will cause movement of pattern cam follower 70 0.250 inches, actuation of solenoid 88c for initiation of movement of adder 76c will cause movement of pattern cam follower 70 0.375 inches and actuation of solenoid 108 for the override mechanism will cause the adder 100 to initiate movement of the override cam follower a distance of 0.125 inches. Thus it will be seen that individual or combinations of solenoids may be used to bring about increments of movement of the pattern cam follower distances as illustrated in the chart of FIG. 3. It will also be seen that the pattern cam follower can be selectively moved to a position for association with a desired pattern cam 66a - g due to the actuation of individual pairs of adders or combinations thereof. It will be appreciated that more or less pairs of adders can be provided to bring about other combinations for selecting differing numbers of pattern cams. 
     FIG. 4 represents an example of a circuit diagram which may be used with the pattern selection mechanism of the invention. The selection switches are illustrated at 92a - 92g as being push button type switches wherein when any one of the switches is depressed the other switches will be reset to an open position. An example of the operation of the circuit is as follows: when a switch 92a is depressed a circuit will be completed through line 118 to line 120 connected to a normally closed relay type switch 116 to which is connected to line 122, connected in turn to the solenoid 108. The circuit is completed through a line 124 which is represented as +24 volts connected to a source of power to complete the circuit through power line 126 having a -24 volts potential. A suitable power source, not illustrated, it provided for supplying 24 volts to the selection system and may comprise a step down transformer connected to the typical 110 volt power source for the machine. 
     As explained above, in relation to the chart illustrated in FIG. 3, when the switch 92a is depressed only the solenoid 108 is activated to position the override cam follower 96 adjacent the override cam 68 and as a result the pattern cam follower 70 is not elevated by the pattern adder mechanism or moved to a position beyond the first pattern cam 66a. As also explained above, when the override cam follower 96 reaches a high point of the override cam 68 a momentary switch represented at 114 will be closed which then connects the line 128 leading from line 118 to the relay switch 116 and energizes the relay to an open position. The opening of the relay switch 116 will then open the circuit to the override solenoid 108 and disconnect the same so that the override adder mechanism will no longer elevate the override cam follower 96 to a position for operable engagement with the override cam 68. The operation of the other switches 92b - 92g is similar to that of switch 92a in that each time one of these latter switches is actuated the solenoid 108 will be actuated for initiating action of the override adder as well as the combination of pattern adders in accordance with the binary selection chart of FIG. 3. Further operation of each of the other switches will be obvious from the circuit diagram. 
     It will be apparent from the above description that a novel and improved electromechanical pattern selection system is provided for a sewing machine capable of producing ornamental patterns. The system includes an adder mechanism wherein movement of the components thereof is very limited thus reducing any problem of noise factor and wear and tear on the components of the adder mechanism. Further it will be seen that the selection system of the invention can be adapted to a standard mechanical pattern cam type sewing machine by merely replacing the mechanical selection system with the novel electromechanical selection system of the invention. While the invention has been described in its preferred embodiment, it will be obvious to those skilled in the art that various modifications and changes may be made therein without departing from the spirit and scope of the invention as defined in the appended claims.