US3884536A

US3884536A - Protective guard device for a transmission shaft

Info

Publication number: US3884536A
Application number: US478314A
Authority: US
Inventors: Theo Buthe
Original assignee: GKN Walterscheid GmbH
Current assignee: Walterscheid GmbH
Priority date: 1973-05-30
Filing date: 1974-06-11
Publication date: 1975-05-20
Anticipated expiration: 1992-05-20
Also published as: JPS5320610B2; AT328803B; IT1013680B; BR7404098D0; NL169215C; ATA194274A; FR2231887B1; DK287374A; CH577121A5; NL169215B; DK134731C; HU169420B; DE2327482A1; ES425297A1; DE2327482B1; JPS5021157A; DK134731B; DE2327482C2; NL7406000A; GB1433077A

Abstract

A protective guard device for a transmission shaft includes a tubular guard member enclosing the transmission shaft and conical guard members at the ends of the tubular member extending over the yoke arms. A radially expandible bearing member is seated in an annular groove formed in either end of the shaft or in a portion of the adjoining yoke arm. A connector interconnects the end of the tubular member to a conical guard member and the connector has a cylindrical surface therein which defines a fitting step having a diameter corresponding to the outer diameter of the bearing member when it is expanded. The bearing member when it is expanded is freely slidable over that portion of the transmission shaft assembly having the annular groove and is then contracted to be seated within the groove.

Description

PROTECTIVE GUARD DEVICE FOR A TRANSMISSION SHAFT [75] Inventor: Theo Buthe, Lohmar, Rhine,

Germany [73] Assignee: Jean Walterscheid GmbII,

Lohmar/ Rhine, Germany [22] Filed: June 11, 1974 [21] Appl. No.: 478,314

[30] Foreign Application Priority Data May 30, 1973 Germany 2327482 [52] US. Cl. 308/37; 64/3; 308/135 [51] Int. Cl. Fl6c 17/10 [58] Field of Search 308/37, 71, 135, 174; 64/3, 4

[56] References Cited UNITED STATES PATENTS 3,194,615 7/1965 Weasler 308/37 3,531,077 9/1970 Trottier et al. 308/37 X [111 3,884,536 [451 May 20, 1975 Primary Examiner-Lloyd L. King Assistant ExaminerMichael Mar Attorney, Agent, or Firm-Edmund M. Jaskiewicz [57] ABSTRACT A protective guard device for a transmission shaft includes a tubular guard member enclosing the transmission shaft and conical guard members at the ends of the tubular member extending over the yoke arms. A radially expandible bearing member is seated in an an nular groove formed in either end of the shaft or in a portion of the adjoining yoke arm. A connector interconnects the end of the tubular member to a conical guard member and the connector has a cylindrical surface therein which defines a fitting step having a diameter corresponding to the outer diameter of the bearing member when it is expanded. The bearing member when it is expanded is freely slidable over that portion of the transmission shaft assembly having the annular groove and is then contracted to be seated within the groove.

8 Claims, 4 Drawing Figures 700 5 8 70b p k I III/4 I n l i 7a 6 The present invention relates to a protective guard device for a transmission shaft having yoke arms at each end thereof, more particularly, to a connector for interconnecting each end of a tubular guard member enclosing the shaft to a respective conical guard member extending over a yoke arm.

It has been known to enclose a transmission shaft with a protective guard device which comprises two telescopingly engaging tubular members with the guard device being supported with respect to the transmission shaft by means of one piece slit annular bearing members seated in a groove on the shaft or on an extension of the respective yoke arm. The bearing member is generally retained in a connector having a stepped configuration which functions to interconnect the tubular guard member with a conical guard member extending over the yoke arm and possibly over the joint connected to the yoke arm. In one such guard device an extension of the transmission shaft is provided with an annular groove in which is seated a tubular bearing member having a plurality of bearing segments. The segments are resilient in a radial direction to facilitate accessibility of the joints during assembly and disassembly of the transmission shaft and for maintenance and service purposes (German patent specification No. 1,188,869). The protective conical guard member, the bearing member and the tubular members can be jointly removed in the axial direction without the use of tools. Since the tubular guard members are retained in position only by the resilient force exerted by the bearing member segments they can be very readily slidingly displaced from their operative positions. This characteristic is contraty to existing regulations for the prevention of accidents which provides that such protective guard devices must not be readily removable from the shaft being protected.

A further disadvantage of this protective guard device is that in removing the guard device the bearing members are removed from their annular grooves and are therefore susceptible to damage and in fact are damaged in the course of frequent repeated fittings and removals. Such damage may affect adversely running conditions.

In another form of a protective guard device the conical or funnel shaped guard member extending over the yoke arm is made in one piece together with the bearing member. Bearing segments are mounted on lugs or tongues and are resilient in the radial direction. After the bearing segments have been seated into the annular grooves, radial expansion of the bearing member and thus displacement of this member is prevented by a guard tube which is slid over the bearing member. (German OS 1 930 278) This guard device has the disadvantage that one must first remove the guard tube and then the conical guard member with the bearing segments in order to gain access to the yoke arms and joint members. As in the abovementioned structure of a guard device this removal may cause damage to the bearing segments.

A further disadvantage is that since the conical member and bearing member are made as a unit it is necessary to fabricate this structure from a plastic material which is suitable for a bearing function. This necessity significantly increases the manufacturing cost of the entire guard device.

A further from of a protective guard device is shown in U.S. Pat. No. 3,194,615 wherein a radially slit bearing member is expanded and pushed over the transmis-' sion shaft extension prior to the assembly of the guard device. The ring is intended to be seated in a correspondingly shaped annular groove on the transmission shaft slide bearing. The conical guard member and the tubular guard member are originally interconnected into a single unit and are pushed over the transmission shaft in a direction toward the joint. This unit engages with the side wall of the slide bearing ring member by means of a spring ring which limits anial displacement. The peripheral surface of the ring engages with a corresponding cylindrically shaped inner surface of the conical guard member. The conical guard member is provided with an opening above the side wall of the slide bearing ring to permit a radially resilient spring clip or washer to be inserted therethr ough. This clip or washer is supported on one side from the side wall of the slide bearing ring and on the otherside along with the opposite side wall thereof from the inner wall of the conical guard member. This construction prevents any axial displacment of the conical and tubular guard members.

While this protective guard device meets the requirement that such a guard device should not be readily removable, it has the disadvantage that the radially resilient spring clip can be assembled and removed only by a skilled workman using special tools should repairs to the joint become necessary. It is difficult to perform such an operation at the site where the shaft is being used which is generally in agricultural machinery.

In still another protective guard device (German Pat. No. 1,207,131) the conical guard member, the connector sleeve and the tubular guard member are mutually locked together and pushed over a previously mounted roller bearing which engages in the annular groove of the transmission shaft so as to be axially locked in position to the outer race ring of this bearing. The guard device is thus axially secured and cannot be readily detached. The bearing member with the roller bearings remains in locked position to offer protection to the bearing when the guard device is disassembled. This guard device, however has the disadvantage that the bearing member together with the roller bearing must be first mounted upon the shaft before the protective guard device can be slidingly positioned over the bearing member. Such a structure is significantly higher in cost since the cost of a roller bearing is greater than that of a bearing member made of plastic material and having slide-bearing segments. Further, after the guard device has been pushed into position, it is locked against axial displacement by fitting a tension strap.

This operation again takes time and tends to unduly complicate the structure.

It is therefore the principal object of the present invention to provide a novel and improved protective guard device for a transmission shaft.

It is another object of the present invention to provide a protective guard device for freely rotating transmission shafts which affords proper protection to any persons in the vicinity of the shaft and which can be removed only with tools but is of a simple and strong construction.

It is a further object of the present invention to provide such a protective guard device which avoids the removal of the bearing member from its normal operating position in order to disassemble the guard device and which thereby prevents damage to the slide bearing surfaces on both the ring and the transmission shaft.

According to one aspect of the present invention the protective guard device for transmission shaft assembly comprising a transmission shaft having yoke arms on the ends thereof may comprise tubular guard means enclosing the transmission shaft. There are annular grooves in the transmission shaft assembly at the junctures of the transmission shaft and the yoke arm. A radially expandible bearing member for each groove is freely slidable over the portion of the transmission shaft assembly having the annular groove therein when in the expanded position and when contatcted is seated into the respective groove. Conical guard members are provided at the ends of the tubular means extending over the respective yoke arms and are interconnected by connectors to the respective ends of the tubular means.

Each connector comprises a locking lug which is engageable with the tubular guard means. Each connector has a cylindrical surface therein which defines a fitting step having a diameter approximately equal to the outer diameter of the bearing member when in the expanded position.

The protective guard device of the present invention is so constructed that a tubular guard member and conical guard member may be removed or assembled onto the transmission shaft in a single operation.

By providing that the bearing member is constructed initially so that in its expanded condition it engages with the inner cylindrical surface the protective guard device consisting of the funnel guard member with the bearing member, connector and tubular guard member can be axially assembled in a single step or operation. The bearing member is expanded only sufficiently to slide freely over the structure in which the annular groove is formed.

Other objects and advantages of the present invention will be apparent upon reference to the accompanying description when taken in conjunction with the following drawings, which are exemplary, wherein:

FIG. 1 is an elevational view partially in longitudinal section of the protective guard device according to the present invention illustrated in the fitting or assembling position;

FIG. 2 is similar to that of FIG. 1 but showing the protective guard device in its operative or assembled position;

FIG. 3 is an elevational view of the connector and bearing member viewed in the direction of the line A-A; and

FIG. 4 is a plane view of the bearing member.

Proceeding next to the drawings wherein like reference symbols indicate the same parts throughout the various views a specific embodiment of the present invention will be described in detail.

As may be seen in FIGS. 1 and 2, a bearing member 1 is made of a synthetic plastic bearing material and has the shape of a one-piece sliding ring having a radial cut or slit 2. Along the inner circumference of bearing member 1 are a plurality of circumferentially spaced bearing segments 3 which are shaped to fit closely within an annular groove 4 formed in a transmission shaft 6 to function as a slide bearing. In order to prevent axial displacement of the bearing member 1 in the direction of the yoke arm 6a the end surface of the bearing member 1 facing the yoke arm rests against a shoulder or flange 5 formed on the yoke arm 6a and extending perpendicularly to the axis of the transmission shaft 6.

The other end surface of bearing member 1 directed toward the transmission shaft 6 engages a surface 5a which is perpendicular to the transmission. shaft axis and which together with flange 5 defines the annular groove 4. When the bearing member 1 is thus seated in the groove 4 it is incapable of axial displacement.

The bearing member 1 is provided with an inclined surface 8 which tapers or drops in the direction toward a tubular guard member 15 which encloses the transmission shaft 6. The inclined surface 8 permits the sliding fitting or mounting of resilient retaining lugs 9 on a connector 10 during the locking operation. The tubular guard member 15 illustrated may be only one part of a tubular guard which may consist of two telescopingly engageable tubular members.

The connector 10 is provided with an inner cylindrical surface 10a which defines a fitting step and has an inclined surface 8a extending downwardly therefrom in the direction toward the transmission shaft 6.

The resilient retaining lugs 9 on the connector 10 have projections 11 which engage in an annular groove 12 formed in the outer peripherial surface of the bearing member 1. On the outer surface of the retaining lugs 9 there are provided reinforcement tabs 13 having slits or recesses 14 at their lower ends adapted to receive a screwdriver blade for the purpose of disengaging the retaining lugs 9 from the bearing member 1 through lever action.

The connector 10 is also provided with a plurality of resilient locking lugs 10b which engage with suitable openings in the tubular guard member 15 to engage lockingly the connector 10 with the tubular guard member.

To facilitate assembly of the bearing member 1, the bearing segments 3 in cross-section are provided with one end forming a radial surface 7 and then extending in a curved configuration outwardly in the direction toward the yoke arm 6a to conform to the curved section 7a of groove 4.

The bearing member 1 is fabricated so that its initial or normal position is expanded to a diameter which corresponds to the inner diameter of the fitting step 10a. As an alternative, the bearing member may also be constructed so that its initial diameter corresponds to the internal diameter of the locking lugs 10b and is maintained in its expanded position by a latch element provided on the inner surface of the fitting step 100.

In assembly, the expanded bearing member 1 is engaged firmly within the cylindrical surface 10a of the connector and then moved axially into the operative position together with the conical guard member 16,

the connector 10 and the tubular guard member 15 without the necessity of any separate or previous assembly or fitting of the bearing member. The bearing member 1 is moved axially therewith until its end surface engages the shoulder 5 on the yoke arm 6a. The bearing member 1 is then stopped from further axial movement and the continued axial movement of the connector 10 causes the

inclined surfaces

8 and 8a to mutually engage and to earn the bearing member 1 inwardly until it is seated into the groove into the position as shown in FIG. 2.Continued movement to the left as viewed in the drawings will enable the locking lugs 9 to become seated in the groove 12 to retain the guard assembly in position.

Once the bearing member has been seated into the groove 4 the assembly of the tubular guard member 15, connector and conical guard member 16 may be removed axially by inserting a screwdriver blade or similar tool into the slit l4 and disengaging the retaining lugs 9 from the bearing member groove 12. During this operation the segments 3 of the bearing member 1 are not removed from the annular groove and consequently they are not susceptible to being damaged. The guard elements together with the connector can thus be disassembled by using two screwdrivers. No special tools are required nor is any particular skill or dexterity required on the part of the operator.

Thus it is apparent that the present invention has disclosed a protective guard assembly for rotating transmission shafts which can be readily assembled or disassembled with a minimum of effort and without the requirement of any special tools. Further, repeated assembly or removal of the protective guard structure will not affect adversely the bearing surfaces of the bearing member since the bearing member remains seated in the bearing groove during subsequent assembly or disassembly of the guard members.

It will be understood that this invention is susceptible to modification in order to adapt it to different usages and conditions, and accordingly, it is desired to comprehend such modifications within this invention as may fall within the scope of the appended claims.

What is claimed is:

1. A protective guard device for a transmission shaft assembly comprising a transmission shaft having yoke arms on the ends thereof and comprising tubular guard means enclosing the transmission shaft, there being annular grooves in said transmission shaft assembly at the junctures of the transmission shaft and the yoke arms, a radially expandible bearing member for each groove freely slidable over the portion of the transmission shaft assembly having the annular grooves therein when in the expanded position and when contracted seated into the respective groove, conical guard members at the ends of said tubular guard means extending over the re spective yoke arms, connectors interconnecting said conical guard members to the respective ends of said tubular guard means and each having a locking lug engageable with said tubular means, said connectors each having a cylindrical surface therein defining a fitting step having a diameter approximately equal to the outer diameter of the bearing member when in the expanded position.

2. A protective guard device as claimed in claim 1 wherein said bearing member has a first inclined surface and said connector has a second inclined surface leading to the fitting step thereof, said inclined surfaces being mutually engageable during assembly of the protective guard device, said first inclined surface tapering inwardly in the direction of said locking lug.

3. A protective guard device as claimed in claim 1 wherein each of said bearing members having a plurality of inner circumferentially spaced bearing segments which seat into a said groove, said bearing members being secured against axial movement when seated in a groove.

4. A protective guard device as claimed in claim 1 wherein there is an external annular groove in said bearing member, and resilient retaining lugs on each of said connectors engageable with said bearing member grooves.

5. A protective guard device as claimed in claim 3 where each of said bearing segments in cross-section has one end curving outwardly in the direction of the respective yoke arm and the other end is perpendicular to the axis of the bearing member.

6. A protective guard device as claimed in claim 1 wherein the end surface of the bearing member directed toward the respective yoke arm is perpendicular to the axis of the bearing member and engages a corresponding surface of said yoke arm.

7. A protective guard device as claimed in claim 1 wherein the bearing member is initially in the expanded position such that its outer diameter corresponds to the inner diameter of said fitting step.

8. A protective guard device as claimed in claim 1 wherein the bearing member has initially an outer diameter corresponding to the inner diameter of said locking lug, and means on said fitting step to maintain the bearing member in the expanded position.

Claims

1. A protective guard device for a transmission shaft assembly comprising a transmission shaft having yoke arms on the ends thereof and comprising tubular guard means enclosing the transmission shaft, there being annular grooves in said transmission shaft assembly at the junctures of the transmission shaft and the yoke arms, a radially expandible bearing member for each groove freely slidable over the portion of the transmission shaft assembly having the annular grooves therein when in the expanded position and when contracted seated into the respective groove, conical guard members at the ends of said tubular guard means extending over the respective yoke arms, connectors interconnecting said conical guard members to the respective ends of said tubular guard means and each having a locking lug engageable with said tubular means, said connectors each having a cylindrical surface therein defining a fitting step having a diameter approximately equal to the outer diameter of the bearing member when in the expanded position.