JPS628752Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention has a plurality of steel balls rotatably held in a retainer arranged on the opposing surfaces of the leg members of an elevating table such as an elevating drafting table and the elevating member. The present invention relates to a linearly movable ball bearing device that is movable in a linear direction with respect to a member.

An elevating member is loosely fitted to the leg member, and a steel ball rotatably held by a retainer is placed between the leg member and the elevating member, so that the elevating member is held movably up and down relative to the leg member. A drafting table has been developed by the applicant. In the above configuration,
When the elevating member is repeatedly moved up and down, the accumulation of minute slips of the steel ball against the leg member and the elevating member causes an error in the rolling movement of the steel ball relative to the leg member and the elevating member, and this error increases. Accumulate in one direction, either upward or downward. Therefore, even if the elevating member is returned to the lowermost position relative to the leg member, the steel balls will not return to the predetermined position that was initially set when the elevating member was in the lowermost position, and the retainer will not move between the leg member and the elevating member. On the other hand, there is a defect that the retainer deviates from the predetermined position by a considerable amount in one direction, that is, upward or downward, and in the worst case, the retainer comes off from between the leg member and the elevating member. Whether the retainer movement error accumulates upward or downward depends on the mechanical properties of the lifting platform. If the elastic force of the gas spring that biases the lifting member upward is greater than the total weight of the lifting member, the retainer will accumulate downward movement error, and if the opposite is true, the retainer will accumulate upward movement error. It has been experimentally confirmed that For example, if the elastic force of the gas spring is greater than the total weight of the elevating member, when the brake on the elevating member is released, the elevating member will suddenly move upward, and conversely, the elastic force of the gas spring will cause the elevating member to move upward. If it is smaller than the total weight of the members, when the brake on the elevating member is released, the elevating member will suddenly move downward, and the inertia at this time will cause the elevating member to slightly slide against the steel ball, causing this slippage. This is thought to be due to the accumulation of Therefore, in order to prevent the retainer from coming off between the leg member and the elevating member, stoppers are provided at the upper and lower ends of the initially set elevating range of the retainer. When the upper end or the lower end collides with the stopper, a large impact is applied between the retainer and the stopper at the time of the collision, resulting in damage to the stopper or retainer. This idea is
The object of this invention is to alleviate the shock caused by the collision between the retainer and the stopper and eliminate the above-mentioned defects.

The configuration of the present invention will be described in detail below based on embodiments shown in the accompanying drawings.

1 is an elevating drafting table, and a pair of horizontal foot levers 2, 2
Leg members 3, 3 are erected, and a connecting shaft 4 is installed between the leg members 3, 3. Reference numerals 5 and 5 designate elevating members that are loosely fitted into the leg members 3, 3, and a connecting shaft 6 is installed between the upper ends of the elevating members 5, 5. 7 is a gas spring, both ends of which are connected to the connecting shafts 4 and 6, and the gas spring 7
The elevating members 5, 5 are elastically pushed upward by the elastic force. Reference numeral 8 denotes a support rod fixed to the upper ends of the elevating members 5, 5, and a drawing plate holder 9 is attached to this. Holding frames 23, 23 are fixed to both parallel sides of the leg member 3 along the longitudinal direction of the leg member 3, and a pair of rail shafts 30, 30a, 30 are attached to the holding frames 23, 23, respectively. ，
30a are fixedly installed parallel to each other. A holding frame 13,
13 is formed, and rail shafts 14, 14, 15, 15 are fixed to the holding frames 13, 13. Stoppers 24 and 25 consisting of a pair of inclined surfaces are formed at a predetermined distance on one side wall of the holding frames 23 and 23 fixed to the leg member 3, and stoppers 24 and 25 consisting of a pair of inclined surfaces are formed on the other side wall as well. Stoppers 24a and 25a are formed with a pair of inclined surfaces spaced apart from each other.
26 is a retainer made of an elastic member, and stoppers 2 made of sloped surfaces are provided on both sides of the main body of the retainer.
7, 28 and 27a, 28a are formed.
A plurality of steel balls 29 rotatably held in the holding part of the retainer 26 are fixed to rail shafts 30, 30a fixed to the holding frame 23 and to the holding frame 13 fixed to the elevating member 5 side. A pair of rail shafts 14, 14, 15, and 15 are arranged in a sandwiched manner.

In the above-described configuration, when the brake pedal 22 is operated to release the fixed state of the elevating members 5, 5 to the leg members 3, 3, the elevating members 5, 5 become free relative to the leg members 3, 3. When force is manually applied in the vertical direction to the elevating members 5, 5 in this state,
The lifting members 5, 5 move up and down along the leg members 3, 3 against the elasticity of the gas spring 7. As the elevating members 5, 5 move, the steel ball 29
Rail shaft 30, 30a, 14, 14, 15, 15
The retainer 26 rolls along the elevating member 5
rail axis 3 with half the amount of movement.
0,30a. At this time, when the retainer 26 reaches the upper end of its set movement range with the upward movement of the elevating member 5, the stopper 27,
27a comes into elastic contact with the stoppers 24, 24a, and a stopping force is applied to the retainer 26 from the stoppers 24, 24a against the rising force. If the retainer 26 is displaced upward, the elevating member 5 is still in a state where it can be raised even if the retainer 26 is stopped by the stoppers 24, 24a, and in this state, the elevating member 5 is manually operated. When the lift member 5 attempts to rise due to this movement, the rail shafts 14 and 15 of the lifting member 5 will slip slightly with respect to the ball 29. This means that the retainer 26 that interlocks with the balls 29 shifts downward relative to the members 5 and 3, and this shift offsets the upward shift of the retainer 26 with respect to the members 5 and 3. Corrected. When the retainer 26 is shifted downward relative to the members 5, 3, the stoppers 28, 28a come into elastic contact with the stoppers 25, 25a as the elevating member 5 descends, and the lowering of the retainer 26 is prevented by the stoppers 25, 25a. Even if it is stopped by , the elevating member 5 is still able to descend. In this state, when the elevating member 5 attempts to descend, the rail shafts 14 and 15 of the elevating member 5 slip slightly relative to the ball 29. This means that the retainer 26 interlocking with the ball 29 is the member 5,
It is an upward shift relative to 3,
This displacement corrects the downward displacement of the retainer 26 with respect to the members 5 and 3. in this way,
The movement error of the retainer 26 with respect to the members 5 and 3 is corrected every time the elevating member 5 moves up and down, and the retainer 26 does not displace significantly from the initially set positional relationship with respect to the members 5 and 3.

As described above, the present invention applies a braking force to the ball retainer disposed between the leg member and the elevating member that can be raised and lowered relative to the leg member, in the vicinity of both ends of the set maximum movement range. As a result, the deviation of the retainer from its original position is corrected each time the elevating member moves, and the retainer's deviation does not accumulate in one direction, making the linear movement of the elevating member smooth. In addition, since at least one of the stoppers that come into contact with the moving end of the lifting member has an inclined surface, the impact of a collision between the stoppers can be reduced, thereby preventing damage to the retainer. There are effects such as being able to prevent.

[Brief explanation of drawings]

The drawings show a preferred embodiment of the present invention; FIG. 1 is a front view of a drafting table, FIG. 2 is a sectional view taken along line A--A, and FIG. 3 is a side view of the main parts. 1... Drafting table, 3... Leg rod member, 5... Lifting member, 13, 13... Holding frame, 14, 15, 30,
30a...Rail axis, 23...Holding frame, 29...
Ball, 26...retainer, 24, 24a, 2
5, 25a, 27, 27a, 28, 28a...stopper.

Claims (1)

[Scope of utility model registration request] A ball holding portion is formed in the retainer 26, and the plurality of balls 29 are rotatably held in the ball holding portion, and the plurality of balls 29 held in the retainer 26 are held between the leg member 3 and the elevating member 5. In this device, the retainer 26 is provided with stoppers 27, 28, 27, and the lifting member 5 is movable within a predetermined range with respect to the leg member 3.
a, 28a, and a stopper 27, which is fixed to the retainer 26 as the elevating member 5 moves up and down.
A holding frame 2 fixedly attached to the leg member 3 and located at at least one end of the lifting path of the legs 28, 27a, and 28a.
3, when the lifting member 5 is located near the end of its movement range, the stoppers 27, 28, 2
a stopper 24 for stopping 7a, 28a;
25, 24a, and 25a, and at least one contact surface of the stoppers that contact each other is an inclined surface.