GB2142472A

GB2142472A - Fastening means for mutually attachable subassemblies

Info

Publication number: GB2142472A
Application number: GB08411246A
Authority: GB
Inventors: Eric Borst; Fritz Schadlich; Manfred Stabler
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1983-06-27
Filing date: 1984-05-02
Publication date: 1985-01-16
Also published as: FR2547873B1; GB2142472B; DE3323057A1; GB8411246D0; DE3323057C2; FR2547873A1

Abstract

In a pair of subassemblies, e.g. a switch housing 7 and a motor housing 1 of a hand tool, which are fastened together by a key 11 and keyway 9 connection, the subassemblies are slidable relative to each other to a stop position. In the stop position, the subassembly 7 with the key 11 is prevented from being lifted out of the open keyway 9 in the other subassembly 1 by interengaging abutments 4,12,5,13,6,14 and is prevented from sliding in the keyway 9 by a resilient tab 17 engaging behind a shoulder 15. The resilient tab 17, which remains accessible from the exterior even after the attachment, can easily be pressed into its unlocking position in order to detach the two subassemblies 1,7 from each other again. <IMAGE>

Description

SPECIFICATION Fastening means for mutually attachable subassemblies The invention starts from fastening means according to the pre-characterising clause of the main claim, It is known to align mutually attachable subassemblies of this type by depressions made in the housing of the larger subassembly mutually with the contours of the housing of the smaller subassembly and to anchor them by screw connections. This method is onerous both in the prefabrication of the components and also in the assembly. The screws required as connection means are losable components. If one of the subassemblies has to be exchanged frequently, the screwthreads, which are mainly cut in plastics, rapidly become damaged. Consequently the housing of the larger subassembly also becomes unserviceable.If the one of the two sub-assemblies is a motor housing of a machine hand tool and the other of the two subassemblies is a switch subassembly, then it frequently occurs that the switch subassembly is definitely anchored only when the motor housing is completely closed. Consequently it is also only then that the switch can be actuated in its correct funtion. It is however advantageous for service in the workshop and for test operations if the electrical tool can also be operated when the tool housing is not completely closed.

Advantages of the invention In contradistinction to the above, the fastening means according to the invention with the characterising features of the main claim possess the advantage that the subassemblies can be mutually attached virtually blindly. Due to the subdivision of the joining movement into simple sections, the fitter's hand is guided securely until the required mutual relative position ofthetwo subassemblies is attained. Advantages in injection moulding technol ogy are also achieved when recesses and guide means are necessary in a technically prescribed direction in at least one of the subassembly hous ings. The open sliding guide means according to the invention and the pockets can easily be placed in the same direction.Thus the injection moulding tool can relatively simply assume this additional moulding function with the existing mould slides. Accumulations of material can also be prevented easily in this manner.

The measures enumerated in the subordinate claims make possible advantageous further develop ments and improvements of the fastening means disclosed in the main claim. The asymmetrical arrangement of the open sliding guide means and/or of the securing elements on the subassemblies to be attached in order to prevent incorrect assembly is particularly advantageous.

Drawing An exemplary embodiment of the object of the invention is illustrated in the drawing and described more fully in the following description.

Figure 1 shows an elevation of two subassemblies mutually attached according to the invention, partly sectioned and Figure2 shows a plan of Figure 1.

Description of the exemplary embodiment A motor housing 1 with a journal 2 required for other purposes and a channel 3 likewise necessary for other purposes has two pockets 4 and 5 and a tab 6 moulded on it. A groove 9 is also machined into the surface 8, which is provided as a contact surface to a switch housing 7. Both the pockets 4 and 5 and the tab 6, and also the groove 9 are oriented in the same direction as the journal 2 and the channel 3. The edges of the groove 9 have introductory surfaces 10.

The groove 9 is also made slightly conical, that is to say it becomes narrower towards the pocket 5 which serves simultaneously as a stop for the switch housing 7. The switch housing 7 has a tongue 11 for engagement in the groove 9, which likewise extends slightly conically correspondingly to this groove 9. A tab 12 on the switch housing 7 is shaped and arranged for engagement into the pocket 4 on the motor housing 1. A tab 13 on the switch housing 7 serves in corresponding manner for engagement in the pocket 5. Lastly, a tab 14 is intended to cooperate with the tab 6 on the motor housing 1.A A nose 15 on the motor housing 1 is aligned in the sliding direction of the switch housing 7 towards the combined stop/pocket 5 and is provided with a rising slope 16 forming the nose ridge.A tab 17 on the switch housing 7, which is resilient transversely to the open sliding guide means 8, 9, 11, 18, is associated with this nose 15. The chosen form and mode of fastening of the resilient tab 17 causes it to be rigid in the direction of the open sliding guide means 8, 9, 11, 18. The contact surface of the switch housing 7 is designated 18. The resilient tab 17 is freely accessible from the exterior above the nose 15. A stop surface 19 on the motor housing 1 is placed opposite the resilient tab 17 so that the latter cannot be overstretched when forced out of its position of engagement, and thus lose its resilience for springing into said position of engagement.

In order to connect the two subassemblies - motor housing 1 and switch housing 7 - the switch housing 7 is first of all placed with the bottom edge of its tongue 11 on the surface 8 of the motor housing 1. It is then slide laterally until the tongue 11 locates in the groove 9, and the surfaces 8 and 18 are in mutual contact. The open sliding guide means constituted by the groove 9 and the tongue 11 and by the surfaces 8 and 18 now direct the movement ofthe switch housing 7 for the engagement of the tabs 12 and13intothepockets4and5andforthetab14to engage beneath the tab 6. In this sliding position, in which the switch housing 7 has not yet reached the stop position on the combined stop/pocket 5, the switch housing 7 can still be moved only in the sliding direction. The resilient tab 17 has then already risen onto the rising slope 16 of the nose 15 and begins to spring inwards. When the sliding movement towards the stop pocket 5 is completed, the resilient tab 17 engages on the nose 15. The switch housing 7 is thus anchored in the required final position on the motor housing 1. In order to release the switch housing 7 from the motor housing 1, the resilient tab 17 is pressed above the nose 15 out of the engaging connection with the nose 15 and draws the switch housing 7 out in the open sliding guide means 8, 9, 11, 18 with the tabs 12 and 13 out of their pockets 4 and 5 and with the tab 14 out from under the tab 6. The switch housing 7 can now be lifted with its contact surface 18 from the surface 8 of the motor housing 1.

Claims

1. Fastening means for mutually attachable subassemblies, particularly for attaching a switch housing to a motor housing of a machine hand tool, with abutment surfaces and edges determining the position of the subassemblies relative to each other, characterised in that the fastening means comprise a longer open sliding guide means (8, 9, 11, 18), a stop (5) to limit the sliding stroke in the one direction, determined by the sliding guide means (8, 9, 11, 18) of the mutual relative movement of the two subassemblies (1,7), shorter securing elements (4, 12; 5, 13; 6, 14) at this end of the sliding stroke to secure against lifting the subassemblies (1,7) out ofthe open sliding guide (8,9, 11, 18), and locking elements (15, 17), the locking elements (15,17) becoming operative when the stop position is reached and preventing the retraction ofthe one subassembly (7) from the stop (5) at the end of the stroke determined by the open sliding guide means (8, 9, 11, 18) and the shorter securing elements (4, 12; 5, 13; 6, 14) so that the subassemblies are anchored relative to each other in their required final position.

2. Fastening means according to Claim 1, characterised in that the long open sliding guide means (8, 9, 11, 18) is a groove and tongue joint with a tongue (11) on the one subassembly (7) and with a groove (9) in the other subassembly (1), combined with contact surfaces (8, 18) of the subassemblies (1, 7).

3. Fastening means according to Claim 1, characterised in that the securing elements are at least three pockets or roofs (4, 5, 6) open in the sliding direction arranged distributed all round the contact surfaces (8, 18) of the subassemblies (1,7) on the one subassembly (1) and an equal number of tabs (12, 13, 14) on the other subassembly (7) intended to engage in these pockets or under these roofs (4,5, 6).

4. Fastening means according to Claim 1, characterised in that the locking means are a stationary nose (15) oriented in the sliding direction to push the subassembly (7) to the stop (5) with a rising slope (16) forming the nose ridge on the one subassembly (1 ) and a tab (17) resilient transversely to the groove and tongue joint, provided with a sloping surface intended to cooperate with the rising slope (16) of the nose (15), rigid in the sliding direction and engageable behind the nose (15), on the other subassembly (7).

5. Fastening means according to Claim 4, characterised in that the resilient tab (17) is accessible in proximity of the nose (15) so that it can be forced out of its engaged position.

6. Fastening means according to Claim 5, characterised in that a stop (19) which is arranged beside the resilienttab (17) and opposite the nose (15) limits the disengaging movement of the resilient tab (17) in order to prevent this resilient tab (17) from being overstretched during disengagement.

7. Fastening means according to Claim 2, characterised in that the groove (9) and the tongue (11) are constructed tapering towards the stop (5).

8. Fastening means according to Claim 1, characterised in that the open sliding guide means (8, 9, 11,18) and/orthe securing elements (4, 12; 5, 13; 6, 14) are arranged asymmetrically to the subassemblies (1, 7).

9. Fastening means substantially as herein described with reference to the accompanying drawing.