GB2166810A

GB2166810A - Pedal crank bearing for bicycles

Info

Publication number: GB2166810A
Application number: GB08506250A
Authority: GB
Inventors: Alfred Heinrich Thun
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-11-14
Filing date: 1985-03-11
Publication date: 1986-05-14
Also published as: DE3441540A1; IT8519973A0; FR2573141A2; CN1003361B; FR2573141B2; GB2166810B; DE3441540C2; GB8506250D0; CN85102071A; IT1185089B

Abstract

A bicycle pedal crank bearing comprises two housing parts (102, 103) which are made pot-shaped, with their mouths directed towards one another, and outer roller races (110) are arranged on the inside of the housing-part bottoms through which the pedal crankshaft passes. The clear width of the housing part (102) adjacent to the pedal crank corresponds at least to the diameter of the adjacent crankshaft shoulder (111) plus double the roller diameter. The bottom bore of the housing part (102) is larger than the maximum pedal crankshaft diameter. A gasket engages into the annular space between the crankshaft (104) and the housing-part bore, and the housing part (102) can be displaced approximately the diameter of the roller out of the position of use towards the pedal crank (105). <IMAGE>

Description

SPECIFICATION Pedal crank bearing for bicycles The invention relates to a pedal crank bearing for bicycles of the type shown in our co-pending application No. 8418470.

Patent Application 8418470 describes a pedal crank bearing which can be preassembled fully operational and subsequently inserted into the frame sleeve and which it is also possible to use on pedal crankshafts having a crank arranged unreleasably at one end of the crankshaft; the opposing flanks of the shoulders arranged on the crankshaft being designed as inner roller races.

Furthermore, the two housing parts are made tubular, their minimum clear width being greater than the crankshaft shoulders and the outer roller faces being arranged respectively on the free end faces of the housing parts screwed to one another.

In addition, covers closing the annular space delimited by the crankshaft and the frame sleeve are attached on the crankshaft, and one cover located at the crankfree end of the pedal crankshaft has a tubular piece engaging positively between the frame sleeve and the housing.

The object of the present invention is to improve a pedal crank bearing in such a way that, whilst the advantages already achieved are preserved, the outer flanks of the shoulders of the pedal crankshaft can be designed as inner roller races, but also the pedal crank bearing can be used for force transmission with free-wheeling or with a free-wheel backpedal brake and, furthermore, can fit frame sleeves both of larger diameter (approximately 40 mm) and of small diameter (approximately 35 mm).

This object is achieved in a way characterised by the following features: a. the housing parts are made essentially pot-shaped and are screwed to one another with their mouths directed towards one another, b. the outer roller races are arranged on the inside of the housing-part bottoms, c. bores which are arranged coaxially relative to the pedal crankshaft and through which the latter passes are provided in the housingpart bottoms, d. the clear width of a first housing part corresponds at least to the diameter of the crankshaft shoulder adjacent to the pedal crank plus double the diameter of a roller, e. the diameter of the bore arranged in the bottom of the first housing part is greater than the maximum diameter of the pedal crankshaft, f. the first housing part is arranged adjacent to the pedal crank together with the chain wheel, g. a gasket engages positively into the annular space limited by the crankshaft and the bottom bore of the first housing part, and h. the first housing part can be displaced approximately the diameter of a roller on the pedal crankshaft (104) out of the position of use towards the unreleasable pedal crank (105).

Because the outer flanks of the pedal crankshaft shoulders are designed as inner roller races, the roller bearings are arranged at a greater axial distance from one another than in the subject of Patent Application P 34 18 499.6, thus resulting in a higher load-carrying capacity of the pedal crank bearing, whilst the same dimensions as hitherto are maintained.

At the same time, the two housing parts can also be attached to the pedal crankshaft from the crank-free end of the latter.

It is nevertheless also guaranteed that the rollers are arranged between the outer and inner roller races assigned to them and that the pedal crank bearing is sealed off from outside.

Furthermore, in the pedal crank bearing described above, it is advantageous if the length of the first housing part corresponds approximately to one third of the length of the entire housing, and if there is in the first housing part a threaded bore, into which is screwed the second housing part having an externalthread zone matching the threaded bore.

This results, on the one hand, in a smaller outside diameter for the second housing part than for the first housing part and, on the other hand, when the pedal crank bearing is inserted into the frame sleeve, in a free annular space which is located between the cylindrical frame sleeve and the second housing part and which among other things makes it possible to guide electrical leads through the latter, without the electrical leads being damaged when the pedal crank bearing is inserted into the frame sleeve.

In this respect, an advantageous development is characterised in that the end part of the second housing part on the mouth side is reduced in diameter approximately over half the total length of the latter in relation to the end part on the bottom side.

It is also advantageous if a block against rotation is associated with the screw connection between the housing parts.

For this purpose, for example, a lock nut screwed onto the external-thread zone of the second housing part and tightened against the mouth end face of the first housing part can be used, in order to ensure the bearing play established before the pedal bearing is inserted into the frame sleeve.

In this respect, an advantageous further development is characterised in that the two housing parts consist of plastic and are screwed to one another in a self-locking way, so that there is no need for the abovementioned lock nut or the like.

At the same time, here too, the outer roller races can under certain circumstances be formed on the housing parts.

However, so that it is possible to use those plastics which are particularly suitable for making self-locking screw connections, but without possessing particularly favourable properties for forming pivot bearings, yet at the same time guaranteeing a high operating capacity for the abovementioned pedal crank bearing, the outer roller races are formed by shells made of metal, especially hardened steel, which are attached unreleasably to the housing parts.

Further designs which both make it easier to assemble the abovementioned pedal crank bearing and are beneficial to achieving a correctly positioned arrangement and permanent retention of the gasket adjacent to the unreleasable crank are disclosed in Claims 8 to 11.

An appliance which makes it particularly simple to assemble the above-described pedal crank bearing is characterised in Claim 12.

An exemplary embodiment of the invention is illustrated in the drawing and described in more detail below. In the drawing: Figure 1 shows a pedal crank bearing in longitudinal section; Figures 2 and 3 show parts of this at different stages of assembly.

According to Fig. 1, a fully operational preassembled pedal crank bearing is inserted into a cylindrical frame sleeve 101 and consists of a housing which is composed of two essentially pot-shaped housing parts 102 and 103 having annular cross-sections and through which a pedal crankshaft 104 passes axially.

Attached unreleasably to one end of the pedal crank-shaft 104 is a pedal crank 105 which carries a chain wheel 106 arranged coaxially relative to the pedal crankshaft 104 and connected firmly to the pedal crankshaft 104.

The housing parts 102 and 103 are arranged with their mouths directed towards one another. To connect them coaxially to one another, a threaded bore 107 is arranged in the housing part 102 and an external-thread zone 108 matching the threaded bore 107 is provided on the periphery of the housing part 103, the external-thread zone 108 being screwed into the threaded bore 107 so as to be adjustable in the axial direction.

An outer roller race 110 is formed on the inside of each of the housing-part bottoms.

Two shoulders 111 arranged at an axial distance from one another are formed on the pedal crankshaft 104, and the outer flanks of these shoulders 111 are designed as inner foller races 112.

A plurality of spherical rollers 113 is inserted between the respective outer and inner roller races 110 and 112 so as to be distributed over the periphery, with a movement play relative to the races, and the amount of the abovementioned movement play can be adjusted as a result of the appropriate screwing of the two housing parts 102 and 103 relative to one another, even before the pedal crank bearing is inserted into the frame sleeve 101.

The housing part 102 arranged adjacent to the pedal crank 105 and the chain wheel 106 is inserted into the frame sleeve 101 with a close sliding fit and also has a formed-on flange 14 which projects radially outwards and which rests against the end face of the frame sleeve 101 adjacent to it.

The maximum diameter of the housing part 103 is approximately once to twice the wall thickness of the frame sleeve 101 less than the clear diameter of the latter, so that the housing part 103 is arranged with a uniform play relative to the wall of the frame sleeve 101 over its entire periphery.

To fix the housing part 103 in the frame sleeve 101, specifically in the radial direction, a tubular piece 118 is inserted positively and frictionally into the annular space formed by the frame sleeve 101 and the housing part 103.

Formed on this tubular piece 118 is a flange 119 which projects radially outwards and which is laid against the end face of the frame sleeve 101 adjacent to it and thus limits the depth of insertion of the tubular piece 118.

To secure the housing positively in the frame sleeve 101 in the axial direction also, there is on the outer end part of the housing part 103 an external-thread zone 120, onto which a screw nut 121 is screwed and tightened against the flange 119.

A sealing ring 123 surrounding the pedal crankshaft 104 without play is retained on the screw nut 121.

The sealing ring 123 is formed on the screw nut 121 made especially of plastic.

In the bottoms of the housing parts 102 and 103 there are bores 124 and 125 respectively which are arranged coaxially relative to the latter.

The bore 124 of the housing part 102 is larger than the maximum diameter of the pedal crankshaft 104, so that the housing part 102 can be pushed over the shoulders 111 formed on the pedal crankshaft 104 onto the latter from its crank-free end.

A gasket 126 is inserted positively into the annular space limited by the shoulder-free zone of the pedal crank-shaft 104 and the bore 124 and is supported frictionally both in the bore 124 and on the pedal crankshaft 104.

A flange 127 is formed on the tubular gasket 126. This flange 127 is laid against the outer end face of the housing part 102 and has a formed-on overlapping edge 128 which positively surrounds the undercut surface of the flange 114.

The gasket 126 consists of elastic material, for example a rubber or plastic, and the overlapping edge 128 is snapped onto the flange 114 under elastic prestress. It is also possible, under certain circumstances, for the gasket 126 to be composed of two parts, for example made of metal, which together form a closed ring, so that even the parts of the gasket 126 which are dimensionally stable per se can nevertheless be inserted into the abovementioned annular space.

To assemble the housing parts 102 and 103 and the rollers 113, according to Fig. 2 the pedal crankshaft 104 is first held with its crank-free end part pointing vertically upwards.

The gasket 126 is then pushed onto the pedal crank-shaft 104, until the gasket 126 comes up against the chain wheel 106. The housing part 102 is then slipped bottom-first onto the pedal crankshafts 104 and coupled to the gasket 126. The rollers 113 are subsequently introduced into the housing part 102.

So that these can pass the pedal crankshaft shoulder 111 adjacent to the pedal crankshaft on the one hand the clear width of the housing part 102 must be greater than the diameter of the abovementioned shoulder 111 plus double the roller diameter.

On the other hand, the housing part 102 must have been displaced approximately one roller diameter out of the position of use illustrated in Fig. 1 towards the chain wheel 106 and the pedal crank 105.

After this, the housing part 102 is shifted upwards, the rollers 113 necessarily being arranged in the correct position between their outer and inner roller races 110 and 112 and also being held temporarily in the correct position in relation to the pedal crankshaft 104 as a result of the frictional arrangement of the housing part 102 via the gasket 126.

Further assembly is preferably carried out with the aid of an assembly appliance consisting essentially of a vertically supported cylindrical bar 129, the length of which corresponds at least to the length of the housing part 103. The housing part 103 is attached bottom first on the bar 129.

The diameter of the bar 129 is approximately double the roller diameter less than the minimum clear width of the housing part 103.

Moreover, the.diameter of the bar 129 must be greater than the diameter of the bore 125 plus the diameter of a roller, so that the rollers 113 introduced into the housing part 103 from above cannot pass through the bore 125.

The free end part of the pedal crankshaft 104 is then aligned coaxially relative to the bar 129 and coupled releasably to the latter, for example by means of a plug connection, as is evident from Fig. 3, and the housing part 103 is then pushed upwards onto the pedal crankshaft 104 and screwed to the housing part 102, after which the housing is released from the bar 129 and the most favourable roller-bearing play set even before insertion into the frame sleeve 101.

A further condition is satisfied at the same time, namely that the minimum clear width of the housing part 103 is greater than the diameter of the shoulder 111 adjacent to the crank-free end part of the pedal crankshaft 104.

To obtain as large a free annular space as possible within the frame sleeve 101 in the middle region, among other things for guiding through electrical leads, for example leading to a rear light, on the one hand the length of the housing part 102 corresponds approximately to one third of the total length of the housing, and the cylindrical end part 130 of the housing part 103 on the mouth side is reduced in diameter in relation to the part of the housing part 103 on the bottom side. At the same time, the length of the end part 130 corresponds aproximately to half the length of the housing part 103.

This results in a bicycle-pedal crank bearing which is suitable both for free wheeling drives and for drives with a back-pedal brake, whereas known "BSA pedal crank bearings", because the roller-bearing play adjustment elements are only inadequately secured, are mainly used only for free-wheeling drives, but known so-called "Thomsen pedal crank bearings" are preferred for drives with back-pedal brakes, although these require a frame sleeve having a larger diameter than "BSA pedal crank bearings".

Claims

1. Pedal-crank bearing for bicycles comprising a housing detachably insertable into the pedal-bearing frame sleeve of a bicycle and through which passes a pedal crankshaft having a pedal crank unreleasably arranged at one end thereof and having two axially spaced shoulders formed thereon which are constructed as inner roller races and opposite which are outer roller races arranged in the housing, revolving rollers being arranged between them; wherein the housing comprises two housing parts which are retained in the frame sleeve and which can be screwed coaxially to one another and which each have a coaxially arranged outer roller race, characterised by the following features: a. the housing parts (102, 103) are made essentially pot-shaped and are screwed to one another with their mouths directed towards one another, b. the outer roller races (110) are arranged on the inside of the housing-part bottoms, c. bores (124, 125) which are arranged coaxially relative to the pedal crankshaft (104) and through which the latter passes are provided in the housing-part bottoms, d. the clear width of a first housing part (102) corresponds at least to the diameter of the crankshaft shoulder (111) adjacent to the pedal crank (105), plus double the diameter of a roller (113), e. the diameter of the bore (124) arranged in the bottom of the first housing part (102) is greater than the maximum diameter of the pedal crankshaft (104), f. the first housing part (102) is arranged adjacent to the pedal crank (105) together with the chain wheel (106), g. a gasket (126) engages positively into the annular space limited by the crankshaft (104) and the bottom bore (124) of the first housing part (102), and h. the first housing part (102) can be displaced approximately the diameter of a roller (113) on the pedal crankshaft (104) out of the position of use towards the unreleasable pedal cranks (105).

2. Pedal crank bearing according to Claim 1, characterised in that the length of the first housing part (102) corresponds approximately to one third of the length of the entire housing, and in the first housing part (102) there is a threaded bore (107), into which is screwed the second housing part (103) having an external-thread zone (108) matching the threaded bore (107).

3. Pedal crank bearing according to Claim 2, characterised in that the end part (130) of the second housing part (103) on the mouth side is reduced in diameter approximately over half the total length of the latter in relation to the end part of the bottom side.

4. Pedal crank bearing according to one of the preceding claims, characterised in that a block against rotation is associated with the screw connection between the housing parts.

5. Pedal crank bearing according to one of the preceding claims, characterised in that the two housing parts (102, 103) consist of plastic and are screwed to one another in a selflocking way.

6. Pedal crank bearing according to one of the preceding claims, characterised by outer roller races (110) formed on the housing parts (102, 103).

7. Pedal crank bearing according to Claim 6, characterised in that the outer roller races (110) are formed by shells made of metal, especially hardened steel, which are attached unreleasably to the housing parts (102, 103).

8. Pedal crank bearing according to one of the preceding claims, characterised in that the gasket (126) is retained on the first housing part (102).

9. Pedal crank bearing according to one of the preceding claims, characterised in that the gasket (126) is arranged so as to be frictionally adjustable in the axial direction on the pedal crankshaft (104).

10. Pedal crank bearing according to one of the preceding claims, characterised in that the gasket (126) has an especially formed-on flange (127) resting against the outside of the bottom of the first housing part (102) and having an overlapping edge (128) which surrounds the first housing part (102) positively on its outer surface.

11. Pedal crank bearing according to Claim 10, characterised in that the first housing part (102) has an undercut flank in the region of the bottom, and the overlapping edge (128) is snapped onto the first housing part (102) so as to surround the undercut flank.

12. Appliance for assembling the abovedescribed pedal bearing according to one of Claims 1 to 11, characterised by a cylindrical bar (129) with devices for aligning it coaxially relative to the pedal crankshaft (104) and for coupling it releasably to the free end of the pedal crankshaft (104), the length of the bar (129) corresponding at least to the length of the second housing part (103) and its diameter on the one hand being approximately double the diameter of a roller (113) less than the minimum clear width of the second housing part (103) and on the other hand being greater than the sum of the diameter of the bore (125) arranged in the bottom of the second housing part (103) plus the diameter of a roller.

13. A pedal crank bearing substantially as described herein with reference to the accompanying drawings.