US 3509640 A
Description (OCR text may contain errors)
y 1970 N. J.- BULLOCK ET 1... 3,509, 40
DOMESTIC DRYER SPEED CONTROL Filed Sept. 5, 1968 v 2 Sheets-Sheet 1 I N VEN TORS 102mm [fizz/0&5
7516: De v13 Q1 4 W ATTORNEY May 5, 1970 N. J. BULLOCK ET AL 3,509,640
DOMESTIC DRYER SPEED CONTROL Filed Sept. 5, 1968 2 Sheets-Sheet 2 ATTORNEY United States Patent 3,509,640 DOMESTIC DRYER SPEED CONTROL Norman J. Bullock and Ted C. Davis, Dayton, Ohio, assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Sept. 3, 1968, Ser. No. 756,915 Int. 'Cl. F26b 11/02 US. Cl. 34133 3 Claims ABSTRACT OF THE DISCLOSURE In preferred form, a domestic dryer apparatus having an outer cabinet surrounding a tumbling drum mounted for rotation on a horizontal axis. An air heating and distribution system directs heated air through the tumbling drum during normal drying wherein the drum is rotated by a belt pulley system. During a no-tumble drying period a drive motor is maintained energized to operate the air blower of the heating system. A belt directed over a drive motor sheave and a periphery of the drum is held away from the drive sheave by an extension on an idler pulley position compensating lever which is shifted to a belt unloading position during no-tumble operation by means including an operator located in the door well of the dryer.
This invention is directed to domestic dryer apparatus and more particularly to domestic dryer apparatus having a no-tumble phase of operation wherein the dryer drum is maintained stationary while a heated air stream is directed through its interior for drying articles therein.
In dryer apparatus of the type having a tumbling drum mounted for rotation about a horizontal axis one suitable drum drive system has been of the type including a single drive belt which is passed over the outer periphery of the drum and a drive sheave to operate the drum during energization of an electric drive motor.
One advantage of a system of this type is that the drive motor is able to concurrently operate a blower motor for circulating heated air across articles in the tumbling drum during a drying phase of operation. A further advantage of a drive system of this type is that it can be continually adjusted during its operation by the inclusion of a low cost idler pulley between the drum periphery and a motor drive sheave to continually compensate for belt slack that occurs during operation.
One system of this type includes a pivot arm and a tension spring for biasing the pivot arm in a direction to move an idler pulley carried on the arm upwardly and against a single belt drive at a point between the periphery of the drum and the drive sheave to tension the belt thereby to produce good driving engagement between drive sheave and drum during motor operation.
Such a system gives a good, low cost, positive drive of a tumbling drum driven on a horizontal axis and assures that articles within the drum will fall through the interior of the drum in a free falling pattern through which a force draft, heated air stream may be passed for quickly removing moisture from the tumbled articles.
It is also recognized in drying apparatus that at times, certain articles might better be dried by locating the articles within the drum interior and allowing the heated, forced draft air stream to pass through the tumbling drum without the articles being tumbled wtihin the drum.
Accordingly, an object of the present invention is to improve the operation of dryer apparatus having a horizontal tumbling drum driven by a drive system including a motor and a single, continuous belt passed over the drive sheave of the motor and the periphery of the drum and wherein the same motor is utilized to operate a blower for distributing heated air through the drum interior during drying operation by the provision of means to release the drive belt tension during a no-tumble phase of dryer operation wherein the drive motor continues to operate the blower to direct heated air through the drum interior and wherein the means for removing tension from the single drive belt also includes means for positioning the single drive belt out of frictional engagement with the drive sheave of the motor thereby to reduce belt wear during the no-tu'mble operation.
A further object of the present invention is to provide a domestic dryer apparatus having a tumble phase of operation and a no-tumble phase of operation wherein a single drive motor concurrently operates a belt pulley system for rotating a horizontal tumbling drum while driving a blower motor to circulate heated air through the interior of the drum; no tumbling action occurring in the drum by removing tension from the belt drive by means that concurrently locates the belt drive completely out of frictional engagement with the drive sheave to prevent excessive frictional wear of the single belt drive during notumble operation.
In one working embodiment the above-stated objects of the present invention are attained in a domestic dryer apparatus of the type including a tumbling drum rotated about a horizontal axis. A single belt member is directed over the periphery of the dryer drum and a drive sheave on a motor that concurrently operates a blower for directing heated air through the tumbling drum. An idler pulley located between the drum periphery and the drive sheave is supported on a pivot arm that is connected to a tension spring that biases the idler pulley against the drive belt to maintain it under tension during a tumble phase of operation. The system includes a push-pull operator having a handle located in the door well of the dryer and which is positionable to a no-tumble control position wherein a wire component of the push-pull operator is connected to the idler pulley pivot arm to back the idler pulley away from the belt to release drive belt tension and thereby stop drum rotation. The means for connecting the push-pull operator to the pivot arm includes a guard extension that concurrently acts on the belt at a point between the idler pulley and thedrive sheave to shift the belt completely out of driving or frictional engagement with the drive sheave to prevent Wear of the belt during no-tumble operation. The push-pull operator has a tumble position wherein the wire component is moved out of coupled engagement with the arm extension and positioned to enable the pivot arm to freely move in response to the force of the tension spring against the belt to drivingly couple the sheave to the drum and to concurrently allow the arm extension to move along with the pivot arm free of the wire to enable the tension spring to shift the idler pulley to continually compensate for belt slack during operation of the dryer.
The foregoing and other objects and advantages of the invention will become apparent from the following description and the accompanying drawings, in which:
FIGURE 1 is a view in perspective of a dryer cabinet having portions thereof broken away to show a belt pulley drive system and manual Operator for conditioning the drive system for a no-tumble phase of drying operation;
FIGURE 2 is an enlarged front elevation view of an operating handle in the inventive system;
FIGURE 3 is an enlarged fragmentary end elevational view of the drive belt and pulley arrangement in the present invention;
FIGURE 4 is a fragmentary end elevational view of the arrangement in FIGURE 3 showing the location of parts of the drive system during a no-tumble phase of drying;
FIGURE 5 is a schematic view of the dryer in FIG- URE 1 showing an air circulation system in the dryer;
FIGURE 6 is a schematic outline drawing of the drive belt path between the tumbling drum of the dryer and its operating motor;
FIGURE 7 is a view like FIGURE 3 showing the operativepositions of the belt drive system following belt slack takeup;
FIGURE 8 is a view in vertical section taken along the line 8-8 of FIGURE 3 looking in the direction of the arrows; and
FIGURE 9 is a view in vertical section taken along the line 9-9 of FIGURE 4 looking in the direction of the arrows.
Referring now to the drawings, in FIGURE 1 a domestic' laundry dryer 10 is illustrated of the type including an'outer cabinet 12 having a top 14, a front 16, spaced apart side walls 18 and 20 connected to the top and front to form an enclosed machinery compartment or space 22, access to which is provided by a rear wall panel 24.
In the illustrated arrangement the front 16 has a door well 26 formed therein formed around an access opening 28 into the interior 30 of tumbling drum 32.
As generally shown in FIGURE 5, the tumbling drum 32 is supported at its rear and front walls by means that support the drum 32 for rotation about a horizontal axis.
In accordance with certain principles of the present invention the drum 32 is operated by an improved belt pulley drive system 34 including an electrically energized drive motor 36 supported on a saddle support 38 fixedly secured to a base framework 40 within the outer cabinet 12 at the bottom thereof.
The drive motor includes a first drive shaft 42 on one end thereof which has a drive sheave 44 fixedly secured thereto.
An upstanding L-shaped bracket 46 has its short leg fixedly secured by suitable fastening means representatively shown as screws 48 to one end of the saddle support 38. The bracket is inclined to one side of the saddle support 38 and has its uppermost end 50 located slightly below the outer periphery of the tumbling drum 32. A pivot pin 52 is directed through the uppermost end 50 and to the fulcrum of a bellcrank compensating member 54. The heads of the pin 52 are formed to receive snap rings that positively interconnect these elements while retaining a desired freedom of pivotal movement therebetween about the pivot point defined by the pin 52.
The bellcrank member 54 includes a first arm 56 depending downwardly of its supported fulcrum point and to one side of the upstanding L-shaped bracket 46 Where it is connected to one end of a tension spring 58 having its opposite end connected to a tab 60, integral with and extending outwardly of the front face of the bracket 46.
A second arm 62 on the member 54 is inclined downwardly of its fulcrum in the general direction of the axis of rotation of the shaft 42; A support pin 64 is carried on the arm 62 as best seen in FIGURES 8 and 9.
An idler pulley 66 on the support pin 64 is located away from the second arm 62 by a spacer element 68, and a washer 70 and snap ring 72 fit over the end of the pin 64 to hold the idler pulley 66 thereon for relative rotation with respect thereto.
The arms 56 and 62 of the bell crank compensating member 54 are configured to cause the idler pulley to be pivoted about the fulcrum of the member 54 along an arcuate path 74 to cause the upper surface of the idler pulley 66 to continually press upwardly against a reach 76 of a continuously formed single poly-V drive belt 78 located between the lowermost part of the outer periphery of the tumbling drum 32 and the drive sheave 44.
The idler pulley 66 thereby serves to maintain the belt 78 in tension through a path extending from the upper surface of the idler pulley 66, thence to the underside of the drum 32 and about its outer periphery, as best seen in FIGURE 6, thence to return from the drum and wrap approximately 180 around the underside of the drive sheave 44 back to the idler pulley 66.
The arcuate path 74 defines the movement of the idler pulley center as it moved by the tension spring 58 to compensate for the slack in the single poly-V drive belt which occurs during normal dryer operation.
The path is upwardly and away from the center line of the drive shaft 42 and, accordingly, there is no tendency for the drive belt to be pinched around the sheave 44 to an extent that might prevent undesirable frictional wear of the belt.
In accordance with certain principles of the present invention the single drive motor 36 has a second drive shaft 80 which is connected to a recirculating blower 82 in an air circulation system shown in FIGURE 5 as including an inlet 84 in the rear panel of the dryer. The system also includes an exhaust port 86 in the panel. The recirculating blower 82 has the outlet thereof connected to a conduit 88 for directing air from the blower through the exhaust port to initiate an air flow pattern from the air inlet 84 thence across a heat source representatively shown as an electrical resistance element 90. Heated air is directed through a plurality of apertures 92 in the rear wall of the tumbling drum 32 and is drawn through the interior 30 of the tumbling drum, thence through the access opening 28 and into exhaust ports 94 formed around the door well 26. The exhaust ports 94 communicate with a duct 96 which communicates with the intake of the recirculating blower 82.
During normal operation a controller 98 on a rearwardly located upper panel of the cabinet 12 is positioned to condition electrical circuit means (not shown) for controlling the energization of the resistance element and the drive motor 36 to concurrently produce a force draft air pattern within the interior of the tumbling drum and a heat input sufiicient to remove moisture from articles being tumbled through the drum during a tumble phase of dryer operation.
Additionally, the illustrated system includes means for conditioning the drive system to produce a no-tumble phase of operation wherein the controller 98 is set in a normal operating position to concurrently energize the resistance element 90 and the drive motor while the belt pulley drive system 34 is manually operated to prevent drum rotation.
Such no-tumble operation has an advantage in that delicate lingerie, and other articles can be placed within the interior of the tumbling drum in a location where the air pattern therein will convectively dry the articles and yet the drum is maintained stationary so that the articles being dried are not subjected to frictional engagement with the interior surface of the drum and distributing vanes normally found therein.
Thus, in accordance with certain principles of the present invention the above-described belt pulley drive system 34 is associated with a manually operated controller 102 that includes an operating arm 104 located in the recessed door well 26 of the outer cabinet 12 and a push-pull operator 106 for connecting the arm 104 to a belt guard and release extension 108 on the lower end of the arm 62.
More particularly and as is best seen in FIGURES l and 2, the operating arm 104 includes a fiat handle portion 110 in the well 26 which is connected to a shaft 112 extending interiorly of the outer cabinet 12. A crankthrow 114 on the shaft 112 is connected to an end extension 116 on shaft 112 fastened against axial movement with respect to a support tab 118 on the cabinet 12 by means of a snap ring 120.
A coil spring 122 is wrapped around the end extension 116 and is biased downwardly against a fiat 124 on the extension 116 to locate the handle 110 at a point that it is readily operated by hand between tumble and no-turnble positions.
At both the tumble and no-tumble positions the flat handle is aligned in close spaced parallelism with the front face of the door well. This permits a door 126- on the outer cabinet 12 to be located within the door well 26 to close the access opening 28. Concurrently, the door 126 will close a switch 128 that is included in the energization circuit for both the resistance element 90 and the drive motor 36.
In any position between the no-turnble and tumble positions the fiat handle 110 will prevent movement of the door 126 into the door well a distance sufficient to operate the switch 128. This assures that the manually operated controller 102 will locate the belt guard and release extension 108 away from belt 78 during normal operation of the drive system 34.
The push-pull operator 106 includes an outer elongated flexible tubular casing 134 of wrapped wire. A pair of spaced-apart lock nuts 136 on one end of the casing 134 fasten it to a support bracket 138 depending from the outer casing 12.
From this fixed point the casing 134 is bent downwardly and extends rearwardly of and along one side of the front 16 of the outer cabinet 12 until it is adjacent the base framework 40. At this point the flexible casing 134 is bent rearwardly until it is at a point adjacent the rear wall panel 24 and then it is bent upwardly to locate the opposite end thereof through a support tab 140 on the L-shaped bracket 46. A pair of lock nuts 142 secure the casing 134 to the tab 140.
The outer surface of the flexible casing 134 is covered by a sheath 143 between its opposite ends to prevent the entrance of dust or the like through the coils of the casing 134. Within the casing 134 is located an elongated spring wire element or push-pull cable 144 that has one end 146 thereof connected to the crankthrow 114 and the opposite end 147 thereof connected to the belt guard and release extension 108.
Referring now more particularly to the belt guard and release extension 108, as best seen in FIGURES 8 and 9, it includes a bent end 148 on the arm 62 that extends above and across the segment of the drive belt 78 between the upper surface of the idler pulley 66 and the drive sheave 44 to a point slightly outboard of the end surface on the drive sheave 44. At this point the bent end 148 is turned to form a distal end 150 on the arm 62 which is approximately perpendicular to the surface of the bent end 148. The distal end 150 has an opening 152 therethrough which receives the operating end 147 of the wire element 144. The operating end 147 has a hooked portion 156 at its terminus.
To produce normal tumbling operation the operating arm 104 is located as seen in solid lines in FIGURE 2. This ushes the push-pull cable Or wire element 144 interiorly of the casing 134 at the fixed bracket 138 and thereby forces the operating end 147 thereof into the position shown in FIGURE 3. The idler pulley 66 is held by the tension spring 58 against the belt reach 76 to positively couple the drive sheave 44 to the drum 36 so as to cause rotation of the drum about its horizontal axis when the motor is energized by the controller 98. In this oper ating mode the hook 156 on the operating end 154 is located a substantial distance above the distal end 150. Accordingly, any slack that might develop in the drive belt 78 is compensated by the tension spring 58 pivoting the bellcrank compensating member 54 about its fulcrum to direct the idler pulley 66 upwardly along the arcuate path 74. The distal end 150 follows a like path and moves freely with respect to the extended operating end 147.
When the manually operated controller 102 has its operating arm located in the no-tumble position, which is shown in dotted lines in FIGURE 2, the wire element 144 is pulled from the casing 134 at the fixed bracket end thereof so as to move the operating end 147 into a retracted position shown in FIGURE 4 of the drawings.
In the no-tumble operating position the hook 156 on the spring wire element is moved to engage the distal end 150 of the compensating member arm 62 so that it will pivot about its fulcrum in a direction opposite to that which occurs during slack compensation. This will cause the idler pulley 66 to move downwardly along the arcuate path 74 and the arm 56 to move in a direction to overcome the biasing action of the tension spring 58. When the idler pulley 66 is thereby unloaded the belt 78 no longer will be tensioned between the drive sheave and the outer periphery of the tumbling drum 32 and, accordingly, drum rotation is stopped.
An important feature of the present invention is that during no-tumble the drive motor 36 is energized by the controller 98 along with the resistance element to maintain a flow of heated air through the circuit illustrated in FIGURE 5. During this type of operation the drive sheave 44 will continue to rotate with respect to the untensioned belt 78. In accordance with certain principles of the present invention the bent end 148 is configured to have a leading edge 158 thereon that is moved upon retraction of the wire element 144 downwardly and against the portion of the tension drive belt between the idler pulley 66 and the drive sheave 44. The bent end 148 thereby serves as a belt guard, moving the belt completely away from the rotating drive sheave 44 during no-tumble operation so that there is no frictional contact therebetween that might undesirably wear the belt during this phase of operation. The bent end 148 thereby serves a dual purpose in that it will produce a first angular movement of the bellcrank compensating member 54, to unload the drive belt 78 thereby to decouple the motor and the tumbling drum; and in response to further retraction of the spring wire element 144 will be moved into a physically interposed position that will shift the belt completely away from the drive sheave to prevent excessive wear.
One aspect of the invention is that the operating end 147 of the push-pull spring wire element follows a path which is substantially tangent to the arcuate path of travel of the idler pulley and thereby is free to move between the perpendicularly arranged distal end 150 on the bent end extension 148 of the arm 62 that follows a like path. Accordingly, there is no tendency for the spring wire element to be jammed between the operating arm and the fixed casing 134 in a manner to interfere with slack compensating movement of the idler pulley and tension spring 58.
In one working embodiment of the above-illustrated no-tumble system the motor 36 is a As horsepower motor driven at 1,750 rpm. The belt length and drum diameter is selected to produce a tumble speed of 49 revolutions per minute and the drum capacity in one operating system is 5.3 cubic feet.
At the above-described speed the blower 82 has a discharge rate of c.f.m. The electrical resistance element, when operated at 240 volts, produces a wattage output of 4,400 watts and, when energized across 120 volts, produces a wattage output of 1,100 watts.
In the operating mode the controller 98, motor, blower and resistance element are operated the same for both tumble and no-tumble operation and the resultant drying action differs only by the tumbling of articles through the interior of the drum as effected by rotation of the drum during tumble operation and eliminated by the improved manually operated system 102 during a no-tumble phase of operation.
While the embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted.
What is claimed is:
1. In a domestic dryer the combination of a horizontal tumbling drum having a peripheral surface thereon, a drive motor for said drum including an output shaft, a drive sheave on said shaft, a continuous belt having a portion thereof directed over said peripheral surface and a portion thereof passed over the underside of said drive sheave, an idler pulley interposed between said drive sheave and said drum, means including a pivoted arm for spring biasing said idler pulley against said belt during operation of said drum, said arm including an extension overlying said drive sheave and being located in overlying relationship with said single belt between said drive sheave and said idler pulley, said extension having a distal end segment, said distal end having an opening therein, a wire having an end extension directed through said distal end opening, a hooked end on said wire, an elongated tubular casing for said wire, means for fixedly securing one end of said casing with respect to said drive sheave, means for fixedly securing the opposite end of said casing, actuator means for operating said wire for moving the hooked end of said wire into a retracted and an extended position, said Wire in a retracted position having the hooked end thereof in engagement with said distal end of said extension for positioning said extension in engagement with said belt between said drive sheave and said idler pulley to move said belt away from said drive sheave and thereby to disconnect said tumbling drum from said drive motor during a no-tumble phase of operation, said actuator means positioning said wire in an extended position during a tumble phase of operation, said hooked end of said wire being positioned out of engagement with said distal end when in its extended position to allow free movement of said pivoted idler pulley arm with respect to said belt thereby to maintain a slack compensating bias between said idler pulley and said belt.
2. In a domestic dryer the combination of an outer cabinet, a tumbling drum located within said cabinet, means for supporting said tumbling drum within said cabinet for rotation about a horizontal axis, means for driving said drum including a drive motor, said drive motor including an output shaft, a sheave connected to said output shaft, a support bracket secured to said cabinet base, a bellcrank having its fulcrum pivotally secured to the upper end of said support bracket, said bellcrank having one arm thereof depending downwardly of said fulcrum} on one side thereof, said bellcrank having a second arm thereon depending downwardly of said fulcrum on the opposite side thereof in a direction toward said sheave, an idler pulley supported on the lower end of said second bellcrank, a tension spring having one end thereof connected to said one bellcrank arm, means for connecting the opposite end of said tension spring to pivot said bellcrank about its fulcrum to cause said idler pulley to be moved upwardly of said drive sheave, a continuously formed single belt wrapped around the outer periphery of said horizontal tumbling drum including a first reach extending from said drum over the upper surface of said idler pulley, said belt extending from the periphery of said drum around the underside of said drive sheave thence to the upper surface of said idler pulley, said idler pulley being moved by said bellcrank upwardly of said drive sheave during compensation of slack in said drive belt along an arc to prevent the belt from being pinched around the outer periphery of said sheave, an extension on the lower end of said second bellcrank arm extending axially of said output shaft at a point above said drive sheave, said extension including a distal end bent with respect to said extension axially outwardly of the axially outermost end of said drive sheave, a wire directed through said distal end of said extension, and actuator means connected to said wire having a no-tumble operating position to retract said wire at said distal end to pull said second arm downwardly and toward said belt between said idler pulley and said drive sheave and in a direction to remove the spring bias of said tension spring from said idler pulley whereby said continuous belt is maintained slack between said drum periphery and said drive sheave to stop drum rotation, said extension having a leading edge thereon engageable with said belt between said retracted idler pulley and said drive sheave to shift said belt downwardly and away from said drive sheave to separate said sheave from said belt when said Wire is in its retracted position thereby to prevent frictional wear of said belt by said sheave, said actuator means having a tumble position to extend said wire at said distal end to allow free upward movement of said extension with respect to said belt thereby to maintain slack compensating bias between said idler pulley and said belt.
3. in a domestic dryer the combination of an outer cabinet having a front access pening, a door well surrounding said opening and defining a recessed space, switchmeans in said well for operating the dryer, a door closure pivotally supported on said cabinet for movement into said door well for closing said opening and to condition said switch means, a tumbling drum located within said cabinet, means for supporting said tumbling drum within said cabinet for rotation about a horizontal axis, means for driving said drumi including a drive motor supported on said cabinet base adjacent the bottom, of said drum, said drive motor including an output shaft, a sheave connected to said output shaft, an upstanding support bracket secured to said cabinet base having the upper end thereof located above the center line of said output shaft and to one side of said drive sheave, a bellcrank having its fulcrum pivotally secured to the upper end of said support bracket, said bellcrank having one arm thereof depending downwardly of said fulcrum on one side thereof, said bellcrank having a second arm thereon depending downwardly of said fulcrum on the opposite side thereof in a direction toward said sheave, an idler pulley supported on the lower end of said second bellcrank, a tension spring having one end thereof connected to said one bellcrank arm, means for connecting the opposite end of said tension spring to pivot said bellcrank about its fulcrum to cause said idler pulley to be moved upwardly of said drive sheave, a continuously formed single belt wrapped around the outer periphery of said horizontal tumbling drum including a first reach extending from said drum, over the upper surface of said idler pulley, said belt extending from the periphery of said drum around the underside of said drive sheave thence to the upper surface of said idler pulley, said idler pulley being moved by said bellcrank upwardly of said drive sheave during compensation of slack in said drive belt along an arc to prevent the belt from being pinched around the outer periphery of said sheave, an extension on the lower end of said second bellcrank arm extending axially of said output shaft at a point above said drive sheave, said extension including a distal end bent with respect to said extension axially outwardly of the axially outermost end of said drive sheave, a wire connected to said distal end of said extension, means for directing said wire through the interior of said cabinet to a location adjacent the door well therein, an actuator handle located I in said door well including a position which precludes door closure and switch operation and a plurality of operating positions where the door can be closed, connecting means for fastening said wire to said actuator handle, said actuator handle having a no-tumble operating position wherein said connecting means retracts said wire at said distal end to pull said second arm downwardly and toward said belt between said idler pulley and said drive sheave and in a direction to remove the spring bias of said tension spring from said idler pulley whereby said continuous belt is maintained slack between said drum periphery and said drive sheave to stop drum rotation, said extension having a leading edge thereon engageable with said belt between said retracted idler pulley and said drive sheave to shift said belt downwardly and away from said drive sheave to separate said sheave from said belt when said wire is in its retracted position References Cited UNITED STATES PATENTS 3,429,056 2/1969 Metzger i34133 LLOYD L. KING, Primary Examiner