US3424880A

US3424880A - Stop motion device

Info

Publication number: US3424880A
Application number: US647967A
Authority: US
Inventors: William K Hope
Original assignee: Hope Plastics Corp
Current assignee: Hope Plastics Corp
Priority date: 1967-06-22
Filing date: 1967-06-22
Publication date: 1969-01-28
Anticipated expiration: 1986-01-28

Description

Filed June 22, 1967 Fig.4

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United States Patent F 3,424,880 STOP MOTION DEVICE William K. Hope, Gastonia, N.C., assignor to Hope Plastics Corp., a corporation of North Carolina Filed June 22, 1967, Ser. No. 647,967 US. Cl. 20061.18 Claims Int. Cl. H0111 23/18 ABSTRACT OF THE DISCLOSURE A stop switch in a textile roving machine closing a stop control circuit when a strand engaging the drop wire becomes excessively slack or ruptures. The pivotal stub shaft to which the drop wire is secured loosely mounts a contact pin, the lower end of which rides on an arcuate contact while the upper end is wedged against one of the downwardly diverging portions of an upper contact should there be excessive swing of the drop wire normally held in a vertical position by the strand.

Background of the invention.-

This invention relates to stop motion switch devices associated with textile machines for automatically stopping operation when a strand of textile material either breaks or acquires an excessive amount of slack.

Stop motion switch devices of the aforementioned type are well known and are generally associated with a drop wire sensing element that is swingable in either direction under the influence of gravity in order to cause pivotal movement of a switch actuating element. The drop wire is ordinarily maintained in a vertical position however by means of the strand or roving being withdrawn between the draft rolls of the machine, the strand extending through an eye portion of the drop wire for this purpose. Excessive swing of the drop wire resulting from either slack of the strand or rupture thereof, closes the contacts of the switch to complete a stop circuit. The present invention resides in the operation, construction and arrangement of the fixed and movable contacts associated with the switch.

It will be appreciated that the textile roving machine with which the present invention is associated, is subject to continuous and substantial vibrations resulting in the rapid wear of parts. Further, such vibrations represent a source of switch malfunction which is a problem in connection with any sensing switch as herein involved. Thus, the provision of a switch having the required sensitivity yet capable of reliable operation despite vibration, represents a significant contribution.

Summary of the invention In accordance with the present invention a stop switch device is provided wherein firm electrical contact is established only when a predetermined amount of angular swing occurs with respect to the drop wire as a result of either rupture of the strand or excessive slack thereof. Toward this end, the pivotal stub shaft to which the drop wire is secured, slidably and loosely mounts a contact pin in sliding contact with a lower, arcuate contact member for all angular positions of the stub shaft and drop wire. The upper end of the contact pin on the other hand is spaced from an upper contact member a sufficient distance to avoid contact while the-drop wire is held in a substantially vertical position by the strand or roving with which it is engaged. Excessive angular swing of the drop wire however brings the upper end of the contact pin into wedging engagement with one of the downwardly diverging portions of the upper contact member in order to firmly establish, through the contact pin, an electrical connection between the upper and lower contact mem- Patented Jan. 28, 1969 bers. The upper and lower contact members are in continuous contact with conductive strips mounted on the frame of the machine to which the stop circuit is connected in the usual manner.

An additional feature of the stop switch, is the provision of a contact pin that is reversible having one end conical in shape. The effective length of the contact pin may accordingly be extended by reversing its position in the actuating element of the switch in order to extend the effective life of the switch device after initial wear of the stop pin following prolonged use of the switch.

Also as a result of the configuration of the movable and fixed contacts associated with the switch, the contact surface area between the movable and fixed contacts is increased as compared to prior art arrangements in order to make operation of the stop device more reliable.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

Brief description of the drawing FIGURE 1 is a diagrammatic view showing a fragmentary part of a roving machine in front elevation.

FIGURE 2 is a partial sectional view taken substantially through a plane indicated by section line 2-2 of FIGURE 1.

FIGURE 3 is a perspective view showing the stop switch device itself.

FIGURE 4 is a rear elevational view of the stop switch device.

FIGURE 5 is a front sectional view of the stop switch device with the cover removed.

FIGURE 6 is a transverse sectional view through the stop switch device taken substantially through a plane indicated by section line 66 of FIGURE 5.

Preferred embodiment of the invention Referring now to the drawings in detail, it will be observed from FIGURES 1 and 2 that a plurality of stop switch devices respectively referred to by reference numeral 10, are fixedly mounted in spaced relation to each other on the frame 12 of a textile roving machine generally referred to by reference numeral 14 below the draft rolls 16 from which textile strands 18 are withdrawn. The strands 18 are withdrawn from-the draft rolls in alignment with the switch devices and extend to the rotating fiyers (not shown) as is well known to those familiar with roving machines. Each strand is thus engaged with one of the drop wires 20 associated with each of the switch devices. Each drop wire includes an eye portion 22 through which a strand extends in order to hold the drop wire in a substantially vertical position from which it may angularly swing in either direction should the strand become excessively slack or rupture. The wire portion 24 of the drop wire is pivotally mounted by an associated switch device about a horizontal axis. The switch devices are mounted in proper position on a non-conductive mounting strip 26 secured in any suitable fashion to the apron 28 of the frame. The mounting strip has embedded therein a pair of

conductor strips

30 and 32 electrically connected to a source of current 34 and a stop solenoid device 36 as diagrammatically shown in FIGURE 1 so as to complete a stop circuit for stopping operation of the roving machine should contacts be closed in any one of the switch devices 10.

As more clearly seen in FIGURES 3 and 6, the wire portion 24 of the drop wire extends through a transverse bore formed in the projecting stub shaft 38 of an actuating element generally referred to by reference numeral 40 preferably made of a non-conductive material. The actuating element is rotatably mounted about a horizontal axis as aforementioned by means of a non-conductive cover 42 secured to the switch housing 44 by means of the fasteners 46. The cover 42 is also provided with slots 48 aligned with slots 50 formed on the back wall 52 of the housing 44 as shown in FIGURE 4 so that the fasteners 54 as shown in FIGURE 1, may secure the switch device to the non-conductive mounting strip 26 just below the upper conductive strip 30. After the switch device is properly mounted, the drop wire is secured in a proper position to the stub shaft 38 by means of the setscrew 56.

The actuating element 40 includes a diametrically enlarged mounting portion 58 enclosed within the housing and piloted on the projection 60 formed therein as shown in FIGURE 6. A bore 62 is formed within the portion 58 for slidably and loosely mounting a contact pin 64 constituting the movable contact element of the switch device. Thus, the contact pin will be angularly displaced by the actuating element 40 in response to angular movement of the drop wire to which it is connected. Further, the contact pin is mounted by the bore 62 in a substantially vertical position intersecting the horizontal rotational .axis of the actuating element and is downwardly urged by the force of gravity into sliding contact with a lower contact member 66.

The lower contact member is fixedly mounted within the housing 44, radially spaced from the actuating element 40 by means of a contact wire 68 that extends rearwardly through an opening in the back wall 52 of the housing having an upwardly extending portion 70 in engagement with the lower conductive strip 32. Also fixedly mounted within the housing by means of another contact wire 72, is an upper contact member 74, the upper contact wire having an end portion 76 in engagement With the conductive strip 30. The lower contact member as shown in FIGURE 5, is arcuate in shape, having a center of curvature which lies substantially on the horizontal rotational axis of the actuating element 40. Thus, the contact pin 64 will ride on the contact member 66 and remain in continuous electrical contact therewith for all angular positions of the actuating element. The contact pin is however spaced from the upper contact member 74 when it is disposed in its vertical position as illustrated in FIGURE 5. The upper contact member is accordingly provided with an apex portion 76 spaced from the upper end of the contact pin and downwardly diverging portions 78 with which the contact pin is adapted to be wedgingly engaged when it is angularly displaced about the axis of the actuating element by an excessive amount.

As shown in FIGURES 5 and 6, the lower end 80 of the contact pin is curved so as to substantially conform to the curvature of the lower contact member 66 with which it is slidingly engaged. The upper end 82 of the contact pin on the other hand is conical in shape so as to not only be spaced in all directions from the apex portion 76 of the upper contact member when the contact pin is in its vertical position but to also firmly engage the downwardly converging portion 78 of the upper contact member along a substantial contact surface. Thus, when the contact pin is wedgingly engaged between the upper and lower contact members, it will be engaged along substantial contact surfaces for reliable electrical contact purposes.

It will be appreciated from the foregoing description, that in view of the spacing between the contact pin 64 and the upper contact member in the vertical position of the drop wire, unintentional contact will be avoided. Also, when the drop wire senses excessive slack or rupture of the textile strand, the contact pin will be wedged between the upper and lower contact members so that vibration of the machine frame cannot adversely affect the established electrical contact. Further, the loose fitting of the contact pin within the bore 62 of the actuating element assures proper electrical contact despite any irregularity in the surface of the lower contact member either because of manufacturing defects or excessive wear of the switch device. The loose fitting of the contact pin within the actuating element also accommodates reversal or inverting thereof so that the conical end 82 may engage the lower contact member. By inverting the contact pin, the effective length of the pin between the upper arid lower contact members is increased and the effective life of the switch device thereby prolonged.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

What is claimed as new is as follows:

1. In a switch for stopping operation of a roving machine in response to excessive slack or rupture of a strand in contact with a drop wire connected to a pivotally mounted actuating element associated with the switch, the improvement comprising a fixed contact member, a movable contact element, means mounting the contact element in the actuating element in sliding contact with the contact member in all angular positions of the drop wire, and wedging contact means mounted in spaced relation to the contact member for wedged engagement of me contact element against the contact member in response to angular displacement of the drop wire by a predetermined amount from a vertical position.

2. The combination of claim 1 wherein said mounting means for the contact element includes a mounting portion of the actuating element in radially spaced alignment between the contact member and the contact means, said mounting portion having a bore through which the contact element slidably and loosely extends.

3. The combination of claim 2 wherein said fixed contact member includes an arcuate portion disposed below the movable contact element gravitationally biased into contact therewith.

4. The combination of claim 3 wherein said wedging contact means comprises an upper contact member having downwardly diverging portions interconnected at an apex portion spaced from the movable contact element in said vertical position of the drop wire.

5. The combination of claim 4 wherein said movable contact element comprises a reversible pin having opposite contact engaging ends projecting radially from said actuating element, one of said ends being conical.

6. The combination of claim 1 wherein said fixed con' tact member includes an arcuate portion disposed below the movable contact element gravitationally biased into contact therewith.

7. The combination of claim 6 wherein said wedging contact means comprises an upper contact member having downwardly diverging portions interconnected at an apex portion spaced from the movable contact element in said vertical position of the drop wire.

8. The combination of claim 7 wherein said movable contact element comprises a reversible pin having opposite contact engaging ends projecting radially from said actuating element, one of said ends being conical.

9. The combination of claim 1 wherein said wedging contact means comprises an upper contact member having downwardly diverging portions interconnected at an apex portion spaced from the movable contact element in said vertical position of the drop wire.

10. A control switch adapted to be actuated by a sensing element comprising, a housing, an actuating element rotatably mounted by the housing about a horizontal axis and connected to said sensing element, a contact pin slidably mounted by said actuating element in a substan- 5 6 tially vertical position intersecting said horizontal axis, References Cited an arcuate contact member fixedly mounted within the housing slidably supporting the contact pin thereabove, UNITED STATES PATENTS said contact member having a center of curvature lying 2,733,308 1/1956 Vossen 200-6113 substantially on said horizontal axis, and an upper con- 5 3,343,008 9/1967 Bancroft 209-6118 tact member fixedly mounted within the housing in radial- 3,379,037 4/ 1968 Antonevlch 20061-18 ly spaced atligrtiment bwith tl 1ie actuatingtelement bandhthe FOREIGN PATENTS arcua e con ac mem er, sai upper con ac mem er av- 656,240 1/1963 Canada ing an apex portion spaced from the contact pin and downwardly diverging portions wedgingly engaged by the I contact pin when angularly displaced by the actuating 10 ROBERT K'SCHAEFERPHmHIy Examine, element from said vertical position. H. O. JONES, Assistant Examiner.